diff --git a/mysql/db/entrypoint/schema.sql b/mysql/db/entrypoint/schema.sql
index 5a86b10..cfdfe0c 100644
--- a/mysql/db/entrypoint/schema.sql
+++ b/mysql/db/entrypoint/schema.sql
@@ -5,6 +5,6 @@ CREATE TABLE event
     group_version INT         NOT NULL,
     exec_id       VARCHAR(32) NOT NULL,
     target_id     VARCHAR(32),
-    event_type    VARCHAR(16) NOT NULL,
+    event_date    DATETIME    NOT NULL,
     event_payload JSON        NOT NULL
 );
diff --git a/mysql/db/schema-heroku.sql b/mysql/db/schema-heroku.sql
index f8bf704..fd92919 100644
--- a/mysql/db/schema-heroku.sql
+++ b/mysql/db/schema-heroku.sql
@@ -1,3 +1,5 @@
+DROP TABLE IF EXISTS event;
+
 CREATE TABLE event
 (
     event_id      INT PRIMARY KEY AUTO_INCREMENT,
@@ -5,6 +7,6 @@ CREATE TABLE event
     group_version INT         NOT NULL,
     exec_id       VARCHAR(32) NOT NULL,
     target_id     VARCHAR(32),
-    event_type    VARCHAR(16) NOT NULL,
+    event_date    DATETIME    NOT NULL,
     event_payload TEXT        NOT NULL
 );
diff --git a/src/main/java/mops/gruppen2/config/KeycloakConfig.java b/src/main/java/mops/gruppen2/config/KeycloakConfig.java
index 3d99c83..74e607d 100644
--- a/src/main/java/mops/gruppen2/config/KeycloakConfig.java
+++ b/src/main/java/mops/gruppen2/config/KeycloakConfig.java
@@ -22,10 +22,10 @@ public class KeycloakConfig {
     @Value("${keycloak.resource}")
     private String clientId;
 
-    @Value("f73354fd-614e-4e24-b801-a8d0f4abf531")
+    @Value("2e2e5770-c454-4d31-be99-9d8c34c93089")
     private String clientSecret;
 
-    @Value("https://gruppenkeycloak.herokuapp.com/auth/realms/master/protocol/openid-connect/token")
+    @Value("https://churl-keycloak.herokuapp.com/auth/realms/Gruppen/protocol/openid-connect/token")
     private String tokenUri;
 
     @Bean
diff --git a/src/main/java/mops/gruppen2/domain/event/AddMemberEvent.java b/src/main/java/mops/gruppen2/domain/event/AddMemberEvent.java
index e294cc1..0394a0c 100644
--- a/src/main/java/mops/gruppen2/domain/event/AddMemberEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/AddMemberEvent.java
@@ -6,7 +6,7 @@ import lombok.Value;
 import lombok.extern.log4j.Log4j2;
 import mops.gruppen2.domain.exception.GroupFullException;
 import mops.gruppen2.domain.exception.IdMismatchException;
-import mops.gruppen2.domain.exception.UserAlreadyExistsException;
+import mops.gruppen2.domain.exception.UserExistsException;
 import mops.gruppen2.domain.model.group.Group;
 import mops.gruppen2.domain.model.group.User;
 import mops.gruppen2.infrastructure.GroupCache;
@@ -39,12 +39,17 @@ public class AddMemberEvent extends Event {
     }
 
     @Override
-    protected void applyEvent(Group group) throws UserAlreadyExistsException, GroupFullException {
+    protected void applyEvent(Group group) throws UserExistsException, GroupFullException {
         group.addMember(target, user);
 
         log.trace("\t\t\t\t\tNeue Members: {}", group.getMembers());
     }
 
+    @Override
+    public String format() {
+        return "Benutzer hinzugefügt: " + target + ".";
+    }
+
     @Override
     public String type() {
         return EventType.ADDMEMBER.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/CreateGroupEvent.java b/src/main/java/mops/gruppen2/domain/event/CreateGroupEvent.java
index c3457cb..8e55353 100644
--- a/src/main/java/mops/gruppen2/domain/event/CreateGroupEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/CreateGroupEvent.java
@@ -39,6 +39,11 @@ public class CreateGroupEvent extends Event {
         log.trace("\t\t\t\t\tNeue Gruppe: {}", group.toString());
     }
 
+    @Override
+    public String format() {
+        return "Gruppe erstellt.";
+    }
+
     @Override
     public String type() {
         return EventType.CREATEGROUP.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/DestroyGroupEvent.java b/src/main/java/mops/gruppen2/domain/event/DestroyGroupEvent.java
index 432c174..d244f3f 100644
--- a/src/main/java/mops/gruppen2/domain/event/DestroyGroupEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/DestroyGroupEvent.java
@@ -20,7 +20,7 @@ public class DestroyGroupEvent extends Event {
 
     @Override
     protected void updateCache(GroupCache cache, Group group) {
-        cache.groupsRemove(group);
+        cache.groupsRemove(groupid, group);
     }
 
     @Override
@@ -30,6 +30,11 @@ public class DestroyGroupEvent extends Event {
         log.trace("\t\t\t\t\tGelöschte Gruppe: {}", group.toString());
     }
 
+    @Override
+    public String format() {
+        return "Gruppe gelöscht.";
+    }
+
     @Override
     public String type() {
         return EventType.DESTROYGROUP.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/Event.java b/src/main/java/mops/gruppen2/domain/event/Event.java
index 7ef6a92..0da2a41 100644
--- a/src/main/java/mops/gruppen2/domain/event/Event.java
+++ b/src/main/java/mops/gruppen2/domain/event/Event.java
@@ -13,21 +13,26 @@ import mops.gruppen2.domain.exception.IdMismatchException;
 import mops.gruppen2.domain.model.group.Group;
 import mops.gruppen2.infrastructure.GroupCache;
 
+import java.time.LocalDateTime;
 import java.util.UUID;
 
+import static com.fasterxml.jackson.annotation.JsonSubTypes.Type;
+import static com.fasterxml.jackson.annotation.JsonTypeInfo.As;
+import static com.fasterxml.jackson.annotation.JsonTypeInfo.Id;
+
 @Log4j2
-@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "class")
-@JsonSubTypes({@JsonSubTypes.Type(value = AddMemberEvent.class, name = "ADDMEMBER"),
-               @JsonSubTypes.Type(value = CreateGroupEvent.class, name = "CREATEGROUP"),
-               @JsonSubTypes.Type(value = DestroyGroupEvent.class, name = "DESTROYGROUP"),
-               @JsonSubTypes.Type(value = KickMemberEvent.class, name = "KICKMEMBER"),
-               @JsonSubTypes.Type(value = SetDescriptionEvent.class, name = "SETDESCRIPTION"),
-               @JsonSubTypes.Type(value = SetInviteLinkEvent.class, name = "SETLINK"),
-               @JsonSubTypes.Type(value = SetLimitEvent.class, name = "SETLIMIT"),
-               @JsonSubTypes.Type(value = SetParentEvent.class, name = "SETPARENT"),
-               @JsonSubTypes.Type(value = SetTitleEvent.class, name = "SETTITLE"),
-               @JsonSubTypes.Type(value = SetTypeEvent.class, name = "SETTYPE"),
-               @JsonSubTypes.Type(value = UpdateRoleEvent.class, name = "UPDATEROLE")})
+@JsonTypeInfo(use = Id.NAME, include = As.PROPERTY, property = "class")
+@JsonSubTypes({@Type(value = AddMemberEvent.class, name = "ADDMEMBER"),
+               @Type(value = CreateGroupEvent.class, name = "CREATEGROUP"),
+               @Type(value = DestroyGroupEvent.class, name = "DESTROYGROUP"),
+               @Type(value = KickMemberEvent.class, name = "KICKMEMBER"),
+               @Type(value = SetDescriptionEvent.class, name = "SETDESCRIPTION"),
+               @Type(value = SetInviteLinkEvent.class, name = "SETLINK"),
+               @Type(value = SetLimitEvent.class, name = "SETLIMIT"),
+               @Type(value = SetParentEvent.class, name = "SETPARENT"),
+               @Type(value = SetTitleEvent.class, name = "SETTITLE"),
+               @Type(value = SetTypeEvent.class, name = "SETTYPE"),
+               @Type(value = UpdateRoleEvent.class, name = "UPDATEROLE")})
 @Getter
 @NoArgsConstructor // Lombok needs a default constructor in the base class
 public abstract class Event {
@@ -44,6 +49,10 @@ public abstract class Event {
     @JsonProperty("target")
     protected String target;
 
+    @JsonProperty("date")
+    protected LocalDateTime date;
+
+    //TODO: Eigentlich sollte die Gruppe aus dem Cache genommen werden, nicht übergeben
     public Event(UUID groupid, String exec, String target) {
         this.groupid = groupid;
         this.exec = exec;
@@ -54,6 +63,7 @@ public abstract class Event {
         if (this.version != 0) {
             throw new BadArgumentException("Event wurde schon initialisiert. (" + type() + ")");
         }
+        date = LocalDateTime.now();
 
         log.trace("Event wurde initialisiert. (" + type() + "," + version + ")");
 
@@ -68,9 +78,22 @@ public abstract class Event {
         }
 
         checkGroupIdMatch(group.getId());
-        updateCache(cache, group);
         group.updateVersion(version);
         applyEvent(group);
+        updateCache(cache, group); // Update erst nachdem apply keine exception geworfen hat
+    }
+
+    public void apply(Group group) throws EventException {
+        log.trace("Event wird angewendet:\t{}", this);
+
+        if (version == 0) {
+            throw new BadArgumentException("Event wurde nicht initialisiert.");
+        }
+
+        checkGroupIdMatch(group.getId());
+        group.updateVersion(version);
+        applyEvent(group);
+
     }
 
     private void checkGroupIdMatch(UUID groupid) throws IdMismatchException {
@@ -88,6 +111,9 @@ public abstract class Event {
 
     protected abstract void applyEvent(Group group) throws EventException;
 
+    @JsonIgnore
+    public abstract String format();
+
     @JsonIgnore
     public abstract String type();
 }
diff --git a/src/main/java/mops/gruppen2/domain/event/KickMemberEvent.java b/src/main/java/mops/gruppen2/domain/event/KickMemberEvent.java
index d5341d0..8d9a080 100644
--- a/src/main/java/mops/gruppen2/domain/event/KickMemberEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/KickMemberEvent.java
@@ -34,6 +34,11 @@ public class KickMemberEvent extends Event {
         log.trace("\t\t\t\t\tNeue Members: {}", group.getMembers());
     }
 
+    @Override
+    public String format() {
+        return "Mitglied entfernt: " + target + ".";
+    }
+
     @Override
     public String type() {
         return EventType.KICKMEMBER.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/SetDescriptionEvent.java b/src/main/java/mops/gruppen2/domain/event/SetDescriptionEvent.java
index f400d98..5ad51dd 100644
--- a/src/main/java/mops/gruppen2/domain/event/SetDescriptionEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/SetDescriptionEvent.java
@@ -38,6 +38,11 @@ public class SetDescriptionEvent extends Event {
         log.trace("\t\t\t\t\tNeue Beschreibung: {}", group.getDescription());
     }
 
+    @Override
+    public String format() {
+        return "Beschreibung gesetzt: " + description + ".";
+    }
+
     @Override
     public String type() {
         return EventType.SETDESCRIPTION.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/SetInviteLinkEvent.java b/src/main/java/mops/gruppen2/domain/event/SetInviteLinkEvent.java
index 72979c4..30c19e7 100644
--- a/src/main/java/mops/gruppen2/domain/event/SetInviteLinkEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/SetInviteLinkEvent.java
@@ -38,6 +38,11 @@ public class SetInviteLinkEvent extends Event {
         log.trace("\t\t\t\t\tNeuer Link: {}", group.getLink());
     }
 
+    @Override
+    public String format() {
+        return "Einladungslink gesetzt: " + link + ".";
+    }
+
     @Override
     public String type() {
         return EventType.SETLINK.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/SetLimitEvent.java b/src/main/java/mops/gruppen2/domain/event/SetLimitEvent.java
index f1b06eb..e69576b 100644
--- a/src/main/java/mops/gruppen2/domain/event/SetLimitEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/SetLimitEvent.java
@@ -36,6 +36,11 @@ public class SetLimitEvent extends Event {
         log.trace("\t\t\t\t\tNeues UserLimit: {}", group.getLimit());
     }
 
+    @Override
+    public String format() {
+        return "Benutzerlimit gesetzt: " + limit + ".";
+    }
+
     @Override
     public String type() {
         return EventType.SETLIMIT.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/SetParentEvent.java b/src/main/java/mops/gruppen2/domain/event/SetParentEvent.java
index 98f5fe9..be1dda9 100644
--- a/src/main/java/mops/gruppen2/domain/event/SetParentEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/SetParentEvent.java
@@ -4,6 +4,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 import lombok.AllArgsConstructor;
 import lombok.Value;
 import lombok.extern.log4j.Log4j2;
+import mops.gruppen2.domain.exception.BadArgumentException;
 import mops.gruppen2.domain.exception.NoAccessException;
 import mops.gruppen2.domain.model.group.Group;
 import mops.gruppen2.domain.model.group.wrapper.Parent;
@@ -29,12 +30,17 @@ public class SetParentEvent extends Event {
     protected void updateCache(GroupCache cache, Group group) {}
 
     @Override
-    protected void applyEvent(Group group) throws NoAccessException {
+    protected void applyEvent(Group group) throws NoAccessException, BadArgumentException {
         group.setParent(exec, parent);
 
         log.trace("\t\t\t\t\tNeues Parent: {}", group.getParent());
     }
 
+    @Override
+    public String format() {
+        return "Veranstaltungszugehörigkeit gesetzt: " + parent.getValue() + ".";
+    }
+
     @Override
     public String type() {
         return EventType.SETPARENT.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/SetTitleEvent.java b/src/main/java/mops/gruppen2/domain/event/SetTitleEvent.java
index 1a5acd6..bdfa3d1 100644
--- a/src/main/java/mops/gruppen2/domain/event/SetTitleEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/SetTitleEvent.java
@@ -38,6 +38,11 @@ public class SetTitleEvent extends Event {
         log.trace("\t\t\t\t\tNeuer Titel: {}", group.getTitle());
     }
 
+    @Override
+    public String format() {
+        return "Titel gesetzt: " + title + ".";
+    }
+
     @Override
     public String type() {
         return EventType.SETTITLE.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/SetTypeEvent.java b/src/main/java/mops/gruppen2/domain/event/SetTypeEvent.java
index b62e09d..85be321 100644
--- a/src/main/java/mops/gruppen2/domain/event/SetTypeEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/SetTypeEvent.java
@@ -3,6 +3,7 @@ package mops.gruppen2.domain.event;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import lombok.AllArgsConstructor;
 import lombok.Value;
+import lombok.experimental.NonFinal;
 import lombok.extern.log4j.Log4j2;
 import mops.gruppen2.domain.exception.EventException;
 import mops.gruppen2.domain.model.group.Group;
@@ -20,6 +21,12 @@ public class SetTypeEvent extends Event {
     @JsonProperty("type")
     Type type;
 
+    //TODO: blöder hack, das soll eigentlich anders gehen
+    // Problem ist, dass die Gruppe vor dem Cache verändert wird, also kann der cache den alten Typ
+    // nicht mehr aus der Gruppe holen
+    @NonFinal
+    Type oldType;
+
     public SetTypeEvent(UUID groupId, String exec, @Valid Type type) {
         super(groupId, exec, null);
 
@@ -28,15 +35,21 @@ public class SetTypeEvent extends Event {
 
     @Override
     protected void updateCache(GroupCache cache, Group group) {
-        cache.typesRemove(group);
+        cache.typesRemove(oldType, group);
         cache.typesPut(type, group);
     }
 
     @Override
     protected void applyEvent(Group group) throws EventException {
+        oldType = group.getType();
         group.setType(exec, type);
     }
 
+    @Override
+    public String format() {
+        return "Gruppentype gesetzt: " + type + ".";
+    }
+
     @Override
     public String type() {
         return EventType.SETTYPE.toString();
diff --git a/src/main/java/mops/gruppen2/domain/event/UpdateRoleEvent.java b/src/main/java/mops/gruppen2/domain/event/UpdateRoleEvent.java
index 4df2fc8..e5f16fb 100644
--- a/src/main/java/mops/gruppen2/domain/event/UpdateRoleEvent.java
+++ b/src/main/java/mops/gruppen2/domain/event/UpdateRoleEvent.java
@@ -38,6 +38,11 @@ public class UpdateRoleEvent extends Event {
         log.trace("\t\t\t\t\tNeue Admin: {}", group.getAdmins());
     }
 
+    @Override
+    public String format() {
+        return "Mitgliedsrolle gesetzt: " + target + ": " + role + ".";
+    }
+
     @Override
     public String type() {
         return EventType.UPDATEROLE.toString();
diff --git a/src/main/java/mops/gruppen2/domain/exception/UserAlreadyExistsException.java b/src/main/java/mops/gruppen2/domain/exception/UserExistsException.java
similarity index 68%
rename from src/main/java/mops/gruppen2/domain/exception/UserAlreadyExistsException.java
rename to src/main/java/mops/gruppen2/domain/exception/UserExistsException.java
index d0288cd..43f5d59 100644
--- a/src/main/java/mops/gruppen2/domain/exception/UserAlreadyExistsException.java
+++ b/src/main/java/mops/gruppen2/domain/exception/UserExistsException.java
@@ -2,11 +2,11 @@ package mops.gruppen2.domain.exception;
 
 import org.springframework.http.HttpStatus;
 
-public class UserAlreadyExistsException extends EventException {
+public class UserExistsException extends EventException {
 
     private static final long serialVersionUID = -8150634358760194625L;
 
-    public UserAlreadyExistsException(String info) {
+    public UserExistsException(String info) {
         super(HttpStatus.INTERNAL_SERVER_ERROR, "User existiert bereits.", info);
     }
 }
diff --git a/src/main/java/mops/gruppen2/domain/model/group/Group.java b/src/main/java/mops/gruppen2/domain/model/group/Group.java
index c081f45..61feb00 100644
--- a/src/main/java/mops/gruppen2/domain/model/group/Group.java
+++ b/src/main/java/mops/gruppen2/domain/model/group/Group.java
@@ -10,7 +10,7 @@ import mops.gruppen2.domain.exception.GroupFullException;
 import mops.gruppen2.domain.exception.IdMismatchException;
 import mops.gruppen2.domain.exception.LastAdminException;
 import mops.gruppen2.domain.exception.NoAccessException;
-import mops.gruppen2.domain.exception.UserAlreadyExistsException;
+import mops.gruppen2.domain.exception.UserExistsException;
 import mops.gruppen2.domain.exception.UserNotFoundException;
 import mops.gruppen2.domain.model.group.wrapper.Body;
 import mops.gruppen2.domain.model.group.wrapper.Description;
@@ -19,6 +19,7 @@ import mops.gruppen2.domain.model.group.wrapper.Link;
 import mops.gruppen2.domain.model.group.wrapper.Parent;
 import mops.gruppen2.domain.model.group.wrapper.Title;
 import mops.gruppen2.domain.service.helper.CommonHelper;
+import mops.gruppen2.domain.service.helper.SortHelper;
 import mops.gruppen2.domain.service.helper.ValidationHelper;
 
 import javax.validation.Valid;
@@ -56,19 +57,21 @@ public class Group {
 
     private GroupMeta meta = GroupMeta.EMPTY();
 
-    private GroupOptions options = GroupOptions.DEFAULT();
+    //TODO: UI set + use for options
+    private final GroupOptions options = GroupOptions.DEFAULT();
 
     // Inhalt
     private Title title = Title.EMPTY();
 
     private Description description = Description.EMPTY();
 
+    //TODO: Asciidoc description
     private Body body;
 
     // Integrationen
 
     // Teilnehmer
-    private Map<String, Membership> memberships = new HashMap<>();
+    private final Map<String, Membership> memberships = new HashMap<>();
 
 
     // ####################################### Members ###########################################
@@ -98,7 +101,7 @@ public class Group {
         return memberships.get(userid).getRole();
     }
 
-    public void addMember(String target, User user) throws UserAlreadyExistsException, GroupFullException {
+    public void addMember(String target, User user) throws UserExistsException, GroupFullException {
         ValidationHelper.throwIfMember(this, target);
         ValidationHelper.throwIfGroupFull(this);
 
@@ -215,6 +218,26 @@ public class Group {
         return !parent.isEmpty();
     }
 
+    public boolean hasMaterial() {
+        return options.isHasMaterialIntegration();
+    }
+
+    public boolean hasForums() {
+        return options.isHasForumsIntegration();
+    }
+
+    public boolean hasCalendar() {
+        return options.isHasTermineIntegration();
+    }
+
+    public boolean hasModules() {
+        return options.isHasModulesIntegration();
+    }
+
+    public boolean hasPortfolios() {
+        return options.isHasPortfolioIntegration();
+    }
+
 
     // ######################################## Setters ##########################################
 
@@ -255,14 +278,20 @@ public class Group {
         this.limit = limit;
     }
 
-    public void setParent(String exec, @Valid Parent parent) throws NoAccessException {
+    public void setParent(String exec, @Valid Parent parent) throws NoAccessException, BadArgumentException {
         ValidationHelper.throwIfNoAdmin(this, exec);
+        if (parent.getValue().equals(groupid)) {
+            throw new BadArgumentException("Die Gruppe kann nicht zu sich selbst gehören!");
+        }
 
         this.parent = parent;
     }
 
     public void setLink(String exec, @Valid Link link) throws NoAccessException {
         ValidationHelper.throwIfNoAdmin(this, exec);
+        if (link.getValue().equals(groupid.toString())) {
+            throw new BadArgumentException("Link kann nicht der GruppenID entsprechen.");
+        }
 
         this.link = link;
     }
@@ -289,7 +318,9 @@ public class Group {
         }
 
         groupid = null;
-        type = null;
+        // Wenn man alles null setzt hat der cache mehr arbeit, weil dieser erst nach der löschung
+        // geupdated wird und sich link und mitgliedschaften selber heraussuchen muss
+        /*type = null;
         parent = null;
         limit = null;
         link = null;
@@ -298,11 +329,11 @@ public class Group {
         title = null;
         description = null;
         body = null;
-        memberships = null;
+        memberships = null;*/
     }
 
     public String format() {
-        return title + " " + description;
+        return title + " - " + description;
     }
 
     @Override
@@ -319,4 +350,8 @@ public class Group {
     public static Group EMPTY() {
         return new Group();
     }
+
+    public long getVersion() {
+        return meta.getVersion();
+    }
 }
diff --git a/src/main/java/mops/gruppen2/domain/model/group/GroupMeta.java b/src/main/java/mops/gruppen2/domain/model/group/GroupMeta.java
index 60372dd..44a7a07 100644
--- a/src/main/java/mops/gruppen2/domain/model/group/GroupMeta.java
+++ b/src/main/java/mops/gruppen2/domain/model/group/GroupMeta.java
@@ -21,6 +21,9 @@ class GroupMeta {
         if (this.version >= version) {
             throw new IdMismatchException("Die Gruppe ist bereits auf einem neueren Stand.");
         }
+        if (this.version + 1 != version) {
+            throw new IdMismatchException("Es fehlen vorherige Events.");
+        }
 
         return new GroupMeta(version, creator, creationDate);
     }
diff --git a/src/main/java/mops/gruppen2/domain/model/group/GroupOptions.java b/src/main/java/mops/gruppen2/domain/model/group/GroupOptions.java
index 88d069a..f0cd1f6 100644
--- a/src/main/java/mops/gruppen2/domain/model/group/GroupOptions.java
+++ b/src/main/java/mops/gruppen2/domain/model/group/GroupOptions.java
@@ -20,6 +20,8 @@ class GroupOptions {
     boolean hasMaterialIntegration;
     boolean hasTermineIntegration;
     boolean hasPortfolioIntegration;
+    boolean hasForumsIntegration;
+    boolean hasModulesIntegration;
 
     static GroupOptions DEFAULT() {
         return new GroupOptions(true,
@@ -31,6 +33,8 @@ class GroupOptions {
                                 null,
                                 true,
                                 true,
+                                true,
+                                true,
                                 true);
     }
 }
diff --git a/src/main/java/mops/gruppen2/domain/model/group/SortHelper.java b/src/main/java/mops/gruppen2/domain/model/group/SortHelper.java
deleted file mode 100644
index 0dbf19d..0000000
--- a/src/main/java/mops/gruppen2/domain/model/group/SortHelper.java
+++ /dev/null
@@ -1,51 +0,0 @@
-package mops.gruppen2.domain.model.group;
-
-import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
-
-import java.util.List;
-
-@NoArgsConstructor(access = AccessLevel.PRIVATE)
-public final class SortHelper {
-
-    /**
-     * Sortiert die übergebene Liste an Gruppen, sodass Veranstaltungen am Anfang der Liste sind.
-     *
-     * @param groups Die Liste von Gruppen die sortiert werden soll
-     */
-    public static void sortByGroupType(List<Group> groups) {
-        groups.sort((Group g1, Group g2) -> {
-            if (g1.getType() == Type.LECTURE) {
-                return -1;
-            }
-            if (g2.getType() == Type.LECTURE) {
-                return 1;
-            }
-
-            if (g1.getType() == Type.PUBLIC) {
-                return -1;
-            }
-
-            if (g2.getType() == Type.PUBLIC) {
-                return 1;
-            }
-
-            return 0;
-        });
-    }
-
-    public static List<Membership> sortByMemberRole(List<Membership> memberships) {
-        memberships.sort((Membership m1, Membership m2) -> {
-            if (m1.getRole() == Role.ADMIN) {
-                return -1;
-            }
-            if (m2.getRole() == Role.ADMIN) {
-                return 1;
-            }
-
-            return 0;
-        });
-
-        return memberships;
-    }
-}
diff --git a/src/main/java/mops/gruppen2/domain/model/group/User.java b/src/main/java/mops/gruppen2/domain/model/group/User.java
index 5fa6802..7f781ca 100644
--- a/src/main/java/mops/gruppen2/domain/model/group/User.java
+++ b/src/main/java/mops/gruppen2/domain/model/group/User.java
@@ -12,6 +12,7 @@ import org.keycloak.adapters.springsecurity.token.KeycloakAuthenticationToken;
 
 @Log4j2
 @Value
+@EqualsAndHashCode(onlyExplicitlyIncluded = true)
 @AllArgsConstructor
 public class User {
 
diff --git a/src/main/java/mops/gruppen2/domain/model/group/wrapper/Link.java b/src/main/java/mops/gruppen2/domain/model/group/wrapper/Link.java
index a79db9a..963dd94 100644
--- a/src/main/java/mops/gruppen2/domain/model/group/wrapper/Link.java
+++ b/src/main/java/mops/gruppen2/domain/model/group/wrapper/Link.java
@@ -4,18 +4,24 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 import lombok.Value;
 
 import javax.validation.constraints.NotNull;
-import javax.validation.constraints.Size;
 import java.util.UUID;
 
 @Value
 public class Link {
 
     @NotNull
-    @Size(min = 36, max = 36)
     @JsonProperty("value")
-    String value;
+    UUID value;
+
+    public Link(String value) {
+        this.value = UUID.fromString(value);
+    }
 
     public static Link RANDOM() {
         return new Link(UUID.randomUUID().toString());
     }
+
+    public String getValue() {
+        return value.toString();
+    }
 }
diff --git a/src/main/java/mops/gruppen2/domain/service/EventStoreService.java b/src/main/java/mops/gruppen2/domain/service/EventStoreService.java
index a7cd712..31ea0b8 100644
--- a/src/main/java/mops/gruppen2/domain/service/EventStoreService.java
+++ b/src/main/java/mops/gruppen2/domain/service/EventStoreService.java
@@ -5,12 +5,16 @@ import lombok.RequiredArgsConstructor;
 import lombok.extern.log4j.Log4j2;
 import mops.gruppen2.domain.event.Event;
 import mops.gruppen2.domain.exception.BadPayloadException;
-import mops.gruppen2.domain.service.helper.JsonHelper;
+import mops.gruppen2.domain.service.helper.CommonHelper;
+import mops.gruppen2.domain.service.helper.FileHelper;
 import mops.gruppen2.persistance.EventRepository;
 import mops.gruppen2.persistance.dto.EventDTO;
 import org.springframework.stereotype.Service;
 
+import java.sql.Timestamp;
+import java.util.Collection;
 import java.util.List;
+import java.util.UUID;
 import java.util.stream.Collectors;
 
 @Log4j2
@@ -52,13 +56,13 @@ public class EventStoreService {
      */
     private static EventDTO getDTOFromEvent(Event event) {
         try {
-            String payload = JsonHelper.serializeEvent(event);
+            String payload = FileHelper.serializeEventJson(event);
             return new EventDTO(null,
                                 event.getGroupid().toString(),
                                 event.getVersion(),
                                 event.getExec(),
                                 event.getTarget(),
-                                event.type(),
+                                Timestamp.valueOf(event.getDate()),
                                 payload);
         } catch (JsonProcessingException e) {
             log.error("Event ({}) konnte nicht serialisiert werden!", event, e);
@@ -81,7 +85,7 @@ public class EventStoreService {
 
     private static Event getEventFromDTO(EventDTO dto) {
         try {
-            return JsonHelper.deserializeEvent(dto.getEvent_payload());
+            return FileHelper.deserializeEventJson(dto.getEvent_payload());
         } catch (JsonProcessingException e) {
             log.error("Payload {} konnte nicht deserialisiert werden!", dto.getEvent_payload(), e);
             throw new BadPayloadException(EventStoreService.class.toString());
@@ -95,4 +99,32 @@ public class EventStoreService {
     public List<Event> findAllEvents() {
         return getEventsFromDTOs(eventStore.findAllEvents());
     }
+
+    public List<Event> findGroupEvents(UUID groupId) {
+        return getEventsFromDTOs(eventStore.findGroupEvents(groupId.toString()));
+    }
+
+    public List<Event> findGroupEvents(List<UUID> ids) {
+        return ids.stream()
+                  .map(id -> eventStore.findGroupEvents(id.toString()))
+                  .map(EventStoreService::getEventsFromDTOs)
+                  .flatMap(Collection::stream)
+                  .collect(Collectors.toList());
+    }
+
+    public List<String> findGroupPayloads(UUID groupId) {
+        return eventStore.findGroupPayloads(groupId.toString());
+    }
+
+    public List<EventDTO> findGroupDTOs(UUID groupid) {
+        return eventStore.findGroupEvents(groupid.toString());
+    }
+
+    public List<UUID> findChangedGroups(long eventid) {
+        return CommonHelper.stringsToUUID(eventStore.findChangedGroupIds(eventid));
+    }
+
+    public long findMaxEventId() {
+        return eventStore.findMaxEventId();
+    }
 }
diff --git a/src/main/java/mops/gruppen2/domain/service/GroupService.java b/src/main/java/mops/gruppen2/domain/service/GroupService.java
index 1522394..9569a67 100644
--- a/src/main/java/mops/gruppen2/domain/service/GroupService.java
+++ b/src/main/java/mops/gruppen2/domain/service/GroupService.java
@@ -24,12 +24,15 @@ import mops.gruppen2.domain.model.group.wrapper.Limit;
 import mops.gruppen2.domain.model.group.wrapper.Link;
 import mops.gruppen2.domain.model.group.wrapper.Parent;
 import mops.gruppen2.domain.model.group.wrapper.Title;
+import mops.gruppen2.domain.service.helper.ValidationHelper;
 import mops.gruppen2.infrastructure.GroupCache;
 import org.springframework.stereotype.Service;
 
+import javax.validation.Valid;
 import java.time.LocalDateTime;
 import java.util.List;
 import java.util.UUID;
+import java.util.stream.Collectors;
 
 /**
  * Behandelt Aufgaben, welche sich auf eine Gruppe beziehen.
@@ -94,9 +97,11 @@ public class GroupService {
      * @param exec     Ausführender User
      */
     public void addUsersToGroup(Group group, String exec, List<User> newUsers) {
-        setLimit(group, exec, getAdjustedUserLimit(newUsers, group));
+        List<User> users = newUsers.stream().distinct().collect(Collectors.toUnmodifiableList());
 
-        newUsers.forEach(newUser -> addUserSilent(group, exec, newUser.getId(), newUser));
+        setLimit(group, exec, getAdjustedUserLimit(users, group));
+
+        users.forEach(newUser -> addUserSilent(group, exec, newUser.getId(), newUser));
     }
 
     /**
@@ -123,6 +128,8 @@ public class GroupService {
      * @throws EventException Falls der User nicht gefunden wird
      */
     public void toggleMemberRole(Group group, String exec, String target) {
+        ValidationHelper.throwIfNoMember(group, target);
+
         updateRole(group, exec, target, group.getRole(target).toggle());
     }
 
@@ -192,7 +199,7 @@ public class GroupService {
      * Prüft, ob der Nutzer Admin ist und ob der Titel valide ist.
      * Bei keiner Änderung wird nichts erzeugt.
      */
-    public void setTitle(Group group, String exec, Title title) {
+    public void setTitle(Group group, String exec, @Valid Title title) {
         if (group.getTitle().equals(title.getValue())) {
             return;
         }
@@ -205,7 +212,7 @@ public class GroupService {
      * Prüft, ob der Nutzer Admin ist und ob die Beschreibung valide ist.
      * Bei keiner Änderung wird nichts erzeugt.
      */
-    public void setDescription(Group group, String exec, Description description) {
+    public void setDescription(Group group, String exec, @Valid Description description) {
         if (group.getDescription().equals(description.getValue())) {
             return;
         }
@@ -231,7 +238,7 @@ public class GroupService {
      * Prüft, ob der Nutzer Admin ist und ob das Limit valide ist.
      * Bei keiner Änderung wird nichts erzeugt.
      */
-    public void setLimit(Group group, String exec, Limit userLimit) {
+    public void setLimit(Group group, String exec, @Valid Limit userLimit) {
         if (userLimit.getValue() == group.getLimit()) {
             return;
         }
@@ -247,7 +254,8 @@ public class GroupService {
         applyAndSave(group, new SetParentEvent(group.getId(), exec, parent));
     }
 
-    public void setLink(Group group, String exec, Link link) {
+    //TODO: UI Link regenerieren button
+    public void setLink(Group group, String exec, @Valid Link link) {
         if (group.getLink().equals(link.getValue())) {
             return;
         }
diff --git a/src/main/java/mops/gruppen2/domain/service/SearchService.java b/src/main/java/mops/gruppen2/domain/service/SearchService.java
index d2bedeb..06b65f3 100644
--- a/src/main/java/mops/gruppen2/domain/service/SearchService.java
+++ b/src/main/java/mops/gruppen2/domain/service/SearchService.java
@@ -4,11 +4,12 @@ import lombok.RequiredArgsConstructor;
 import lombok.extern.log4j.Log4j2;
 import mops.gruppen2.domain.exception.EventException;
 import mops.gruppen2.domain.model.group.Group;
-import mops.gruppen2.domain.model.group.SortHelper;
+import mops.gruppen2.domain.model.group.Type;
 import mops.gruppen2.infrastructure.GroupCache;
 import org.springframework.stereotype.Service;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -30,25 +31,35 @@ public class SearchService {
      *
      * @throws EventException Projektionsfehler
      */
-    //TODO: search in lectures
-    public List<Group> search(String search, String principal) {
+    public List<Group> searchString(String search, String principal) {
         List<Group> groups = new ArrayList<>();
         groups.addAll(groupCache.publics());
         groups.addAll(groupCache.lectures());
         groups = removeUserGroups(groups, principal);
-        SortHelper.sortByGroupType(groups);
 
         if (search.isEmpty()) {
             return groups;
         }
 
         log.debug("Es wurde gesucht nach: {}", search);
-
         return groups.stream()
                      .filter(group -> group.format().toLowerCase().contains(search.toLowerCase()))
                      .collect(Collectors.toList());
     }
 
+    public List<Group> searchType(Type type, String principal) {
+        log.debug("Es wurde gesucht nach: {}", type);
+
+        if (type == Type.LECTURE) {
+            return removeUserGroups(groupCache.lectures(), principal);
+        }
+        if (type == Type.PUBLIC) {
+            return removeUserGroups(groupCache.publics(), principal);
+        }
+
+        return Collections.emptyList();
+    }
+
     private static List<Group> removeUserGroups(List<Group> groups, String principal) {
         return groups.stream()
                      .filter(group -> !group.isMember(principal))
diff --git a/src/main/java/mops/gruppen2/domain/service/helper/APIHelper.java b/src/main/java/mops/gruppen2/domain/service/helper/APIHelper.java
index 906d979..7f1d283 100644
--- a/src/main/java/mops/gruppen2/domain/service/helper/APIHelper.java
+++ b/src/main/java/mops/gruppen2/domain/service/helper/APIHelper.java
@@ -3,13 +3,24 @@ package mops.gruppen2.domain.service.helper;
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
 import lombok.extern.log4j.Log4j2;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.infrastructure.api.GroupRequestWrapper;
+import mops.gruppen2.infrastructure.api.GroupWrapper;
+
+import java.util.List;
+import java.util.stream.Collectors;
 
-//TODO: sinnvolles format
 @Log4j2
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class APIHelper {
 
-    /*public static GroupRequestWrapper wrap(long status, List<Group> groupList) {
-        return new GroupRequestWrapper(status, groupList);
-    }*/
+    public static GroupRequestWrapper wrap(long status, List<Group> groupList) {
+        return new GroupRequestWrapper(status, wrap(groupList));
+    }
+
+    public static List<GroupWrapper> wrap(List<Group> groups) {
+        return groups.stream()
+                     .map(GroupWrapper::new)
+                     .collect(Collectors.toUnmodifiableList());
+    }
 }
diff --git a/src/main/java/mops/gruppen2/domain/service/helper/CommonHelper.java b/src/main/java/mops/gruppen2/domain/service/helper/CommonHelper.java
index 4694501..25a8575 100644
--- a/src/main/java/mops/gruppen2/domain/service/helper/CommonHelper.java
+++ b/src/main/java/mops/gruppen2/domain/service/helper/CommonHelper.java
@@ -4,7 +4,9 @@ import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
 import lombok.extern.log4j.Log4j2;
 
+import java.util.List;
 import java.util.UUID;
+import java.util.stream.Collectors;
 
 @Log4j2
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
@@ -13,4 +15,10 @@ public final class CommonHelper {
     public static boolean uuidIsEmpty(UUID uuid) {
         return "00000000-0000-0000-0000-000000000000".equals(uuid.toString());
     }
+
+    public static List<UUID> stringsToUUID(List<String> changedGroupIds) {
+        return changedGroupIds.stream()
+                              .map(UUID::fromString)
+                              .collect(Collectors.toUnmodifiableList());
+    }
 }
diff --git a/src/main/java/mops/gruppen2/domain/service/helper/CsvHelper.java b/src/main/java/mops/gruppen2/domain/service/helper/CsvHelper.java
deleted file mode 100644
index c087540..0000000
--- a/src/main/java/mops/gruppen2/domain/service/helper/CsvHelper.java
+++ /dev/null
@@ -1,48 +0,0 @@
-package mops.gruppen2.domain.service.helper;
-
-import com.fasterxml.jackson.databind.ObjectReader;
-import com.fasterxml.jackson.dataformat.csv.CsvMapper;
-import com.fasterxml.jackson.dataformat.csv.CsvSchema;
-import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
-import lombok.extern.log4j.Log4j2;
-import mops.gruppen2.domain.exception.EventException;
-import mops.gruppen2.domain.exception.WrongFileException;
-import mops.gruppen2.domain.model.group.User;
-import org.springframework.web.multipart.MultipartFile;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.Collections;
-import java.util.List;
-import java.util.stream.Collectors;
-
-@Log4j2
-@NoArgsConstructor(access = AccessLevel.PRIVATE)
-public final class CsvHelper {
-
-    public static List<User> readCsvFile(MultipartFile file) throws EventException {
-        if (file == null || file.isEmpty()) {
-            return Collections.emptyList();
-        }
-
-        try {
-            List<User> userList = read(file.getInputStream());
-            return userList.stream()
-                           .distinct()
-                           .collect(Collectors.toList()); //filter duplicates from list
-        } catch (IOException e) {
-            log.error("File konnte nicht gelesen werden!", e);
-            throw new WrongFileException(file.getOriginalFilename());
-        }
-    }
-
-    private static List<User> read(InputStream stream) throws IOException {
-        CsvMapper mapper = new CsvMapper();
-
-        CsvSchema schema = mapper.schemaFor(User.class).withHeader().withColumnReordering(true);
-        ObjectReader reader = mapper.readerFor(User.class).with(schema);
-
-        return reader.<User>readValues(stream).readAll();
-    }
-}
diff --git a/src/main/java/mops/gruppen2/domain/service/helper/FileHelper.java b/src/main/java/mops/gruppen2/domain/service/helper/FileHelper.java
new file mode 100644
index 0000000..78857a6
--- /dev/null
+++ b/src/main/java/mops/gruppen2/domain/service/helper/FileHelper.java
@@ -0,0 +1,148 @@
+package mops.gruppen2.domain.service.helper;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.ObjectReader;
+import com.fasterxml.jackson.dataformat.csv.CsvMapper;
+import com.fasterxml.jackson.dataformat.csv.CsvSchema;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+import lombok.extern.log4j.Log4j2;
+import mops.gruppen2.domain.event.Event;
+import mops.gruppen2.domain.exception.EventException;
+import mops.gruppen2.domain.exception.GroupNotFoundException;
+import mops.gruppen2.domain.exception.WrongFileException;
+import mops.gruppen2.domain.model.group.User;
+import mops.gruppen2.persistance.dto.EventDTO;
+import org.springframework.web.multipart.MultipartFile;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+@Log4j2
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public final class FileHelper {
+
+    // ######################################## CSV #############################################
+
+
+    public static List<User> readCsvFile(MultipartFile file) throws EventException {
+        if (file == null || file.isEmpty()) {
+            return Collections.emptyList();
+        }
+
+        try {
+            List<User> userList = readCsv(file.getInputStream());
+            return userList.stream()
+                           .distinct()
+                           .collect(Collectors.toList()); //filter duplicates from list
+        } catch (IOException e) {
+            log.error("File konnte nicht gelesen werden!", e);
+            throw new WrongFileException(file.getOriginalFilename());
+        }
+    }
+
+    private static List<User> readCsv(InputStream stream) throws IOException {
+        CsvMapper mapper = new CsvMapper();
+
+        CsvSchema schema = mapper.schemaFor(User.class).withHeader().withColumnReordering(true);
+        ObjectReader reader = mapper.readerFor(User.class).with(schema);
+
+        return reader.<User>readValues(stream).readAll();
+    }
+
+    public static String writeCsvUserList(List<User> members) {
+        StringBuilder builder = new StringBuilder();
+        builder.append("id,givenname,familyname,email\n");
+
+        members.forEach(user -> builder.append(user.getId())
+                                       .append(",")
+                                       .append(user.getGivenname())
+                                       .append(",")
+                                       .append(user.getFamilyname())
+                                       .append(",")
+                                       .append(user.getEmail())
+                                       .append("\n"));
+
+        return builder.toString();
+    }
+
+
+    // ########################################## JSON ###########################################
+
+
+    /**
+     * Übersetzt eine Java-Event-Repräsentation zu einem JSON-Event-Payload.
+     *
+     * @param event Java-Event-Repräsentation
+     *
+     * @return JSON-Event-Payload als String
+     *
+     * @throws JsonProcessingException Bei JSON Fehler
+     */
+
+    public static String serializeEventJson(Event event) throws JsonProcessingException {
+        ObjectMapper mapper = new ObjectMapper().registerModule(new JavaTimeModule());
+        String payload = mapper.writeValueAsString(event);
+        log.trace(payload);
+        return payload;
+    }
+
+    /**
+     * Übersetzt eine JSON-Event-Payload zu einer Java-Event-Repräsentation.
+     *
+     * @param json JSON-Event-Payload als String
+     *
+     * @return Java-Event-Repräsentation
+     *
+     * @throws JsonProcessingException Bei JSON Fehler
+     */
+    public static Event deserializeEventJson(String json) throws JsonProcessingException {
+        ObjectMapper mapper = new ObjectMapper().registerModule(new JavaTimeModule());
+        Event event = mapper.readValue(json, Event.class);
+        log.trace(event);
+        return event;
+    }
+
+
+    // ############################################### TXT #######################################
+
+
+    public static String payloadsToPlain(List<String> payloads) {
+        return payloads.stream()
+                       .map(payload -> payload + "\n")
+                       .reduce((String payloadA, String payloadB) -> payloadA + payloadB)
+                       .orElseThrow(() -> new GroupNotFoundException("Keine Payloads gefunden."));
+    }
+
+    public static String eventDTOsToSql(List<EventDTO> dtos) {
+        StringBuilder builder = new StringBuilder();
+
+        builder.append("INSERT INTO event(group_id, group_version, exec_id, target_id, event_date, event_payload)\nVALUES\n");
+
+        dtos.forEach(dto -> builder.append("('")
+                                   .append(dto.getGroup_id())
+                                   .append("','")
+                                   .append(dto.getGroup_version())
+                                   .append("','")
+                                   .append(dto.getExec_id())
+                                   .append("','")
+                                   .append(dto.getTarget_id())
+                                   .append("','")
+                                   .append(dto.getEvent_date())
+                                   .append("','")
+                                   .append(dto.getEvent_payload())
+                                   .append("'),\n"));
+
+        builder.replace(builder.length() - 2, builder.length(), ";");
+
+        return builder.toString();
+    }
+
+
+    // ############################################### SQL #######################################
+}
diff --git a/src/main/java/mops/gruppen2/domain/service/helper/JsonHelper.java b/src/main/java/mops/gruppen2/domain/service/helper/JsonHelper.java
deleted file mode 100644
index b66c57f..0000000
--- a/src/main/java/mops/gruppen2/domain/service/helper/JsonHelper.java
+++ /dev/null
@@ -1,50 +0,0 @@
-package mops.gruppen2.domain.service.helper;
-
-import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
-import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
-import lombok.extern.log4j.Log4j2;
-import mops.gruppen2.domain.event.Event;
-
-/**
- * Übersetzt JSON-Event-Payloads zu Java-Event-Repräsentationen und zurück.
- */
-@Log4j2
-@NoArgsConstructor(access = AccessLevel.PRIVATE)
-public final class JsonHelper {
-
-    /**
-     * Übersetzt eine Java-Event-Repräsentation zu einem JSON-Event-Payload.
-     *
-     * @param event Java-Event-Repräsentation
-     *
-     * @return JSON-Event-Payload als String
-     *
-     * @throws JsonProcessingException Bei JSON Fehler
-     */
-
-    public static String serializeEvent(Event event) throws JsonProcessingException {
-        ObjectMapper mapper = new ObjectMapper().registerModule(new JavaTimeModule());
-        String payload = mapper.writeValueAsString(event);
-        log.trace(payload);
-        return payload;
-    }
-
-    /**
-     * Übersetzt eine JSON-Event-Payload zu einer Java-Event-Repräsentation.
-     *
-     * @param json JSON-Event-Payload als String
-     *
-     * @return Java-Event-Repräsentation
-     *
-     * @throws JsonProcessingException Bei JSON Fehler
-     */
-    public static Event deserializeEvent(String json) throws JsonProcessingException {
-        ObjectMapper mapper = new ObjectMapper().registerModule(new JavaTimeModule());
-        Event event = mapper.readValue(json, Event.class);
-        log.trace(event);
-        return event;
-    }
-}
diff --git a/src/main/java/mops/gruppen2/domain/service/helper/ProjectionHelper.java b/src/main/java/mops/gruppen2/domain/service/helper/ProjectionHelper.java
index f4f9011..2e686e9 100644
--- a/src/main/java/mops/gruppen2/domain/service/helper/ProjectionHelper.java
+++ b/src/main/java/mops/gruppen2/domain/service/helper/ProjectionHelper.java
@@ -7,6 +7,9 @@ import mops.gruppen2.domain.event.Event;
 import mops.gruppen2.domain.model.group.Group;
 import mops.gruppen2.infrastructure.GroupCache;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
@@ -19,6 +22,21 @@ import java.util.UUID;
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class ProjectionHelper {
 
+    public static List<Group> project(List<Event> events) {
+        Map<UUID, Group> groups = new HashMap<>();
+
+        if (events.isEmpty()) {
+            return Collections.emptyList();
+        }
+
+        log.trace(groups);
+        log.trace(events);
+
+        events.forEach(event -> event.apply(getOrCreateGroup(groups, event.getGroupid())));
+
+        return new ArrayList<>(groups.values());
+    }
+
     public static void project(Map<UUID, Group> groups, List<Event> events, GroupCache cache) {
         if (events.isEmpty()) {
             return;
diff --git a/src/main/java/mops/gruppen2/domain/service/helper/SortHelper.java b/src/main/java/mops/gruppen2/domain/service/helper/SortHelper.java
new file mode 100644
index 0000000..2f7583f
--- /dev/null
+++ b/src/main/java/mops/gruppen2/domain/service/helper/SortHelper.java
@@ -0,0 +1,27 @@
+package mops.gruppen2.domain.service.helper;
+
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+import mops.gruppen2.domain.model.group.Membership;
+import mops.gruppen2.domain.model.group.Role;
+
+import java.util.List;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public final class SortHelper {
+
+    public static List<Membership> sortByMemberRole(List<Membership> memberships) {
+        memberships.sort((Membership m1, Membership m2) -> {
+            if (m1.getRole() == Role.ADMIN) {
+                return -1;
+            }
+            if (m2.getRole() == Role.ADMIN) {
+                return 1;
+            }
+
+            return 0;
+        });
+
+        return memberships;
+    }
+}
diff --git a/src/main/java/mops/gruppen2/domain/service/helper/ValidationHelper.java b/src/main/java/mops/gruppen2/domain/service/helper/ValidationHelper.java
index 4e3ddd5..c82fff4 100644
--- a/src/main/java/mops/gruppen2/domain/service/helper/ValidationHelper.java
+++ b/src/main/java/mops/gruppen2/domain/service/helper/ValidationHelper.java
@@ -7,7 +7,7 @@ import mops.gruppen2.domain.exception.BadArgumentException;
 import mops.gruppen2.domain.exception.GroupFullException;
 import mops.gruppen2.domain.exception.LastAdminException;
 import mops.gruppen2.domain.exception.NoAccessException;
-import mops.gruppen2.domain.exception.UserAlreadyExistsException;
+import mops.gruppen2.domain.exception.UserExistsException;
 import mops.gruppen2.domain.exception.UserNotFoundException;
 import mops.gruppen2.domain.model.group.Group;
 import mops.gruppen2.domain.model.group.Type;
@@ -39,10 +39,10 @@ public final class ValidationHelper {
     // ######################################## THROW ############################################
 
 
-    public static void throwIfMember(Group group, String userid) throws UserAlreadyExistsException {
+    public static void throwIfMember(Group group, String userid) throws UserExistsException {
         if (group.isMember(userid)) {
             log.error("Benutzer {} ist schon in Gruppe {}", userid, group);
-            throw new UserAlreadyExistsException(userid);
+            throw new UserExistsException(userid);
         }
     }
 
diff --git a/src/main/java/mops/gruppen2/infrastructure/GroupCache.java b/src/main/java/mops/gruppen2/infrastructure/GroupCache.java
index d3999fd..9dc33de 100644
--- a/src/main/java/mops/gruppen2/infrastructure/GroupCache.java
+++ b/src/main/java/mops/gruppen2/infrastructure/GroupCache.java
@@ -3,6 +3,8 @@ package mops.gruppen2.infrastructure;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.log4j.Log4j2;
 import mops.gruppen2.domain.exception.GroupNotFoundException;
+import mops.gruppen2.domain.exception.IdMismatchException;
+import mops.gruppen2.domain.exception.UserNotFoundException;
 import mops.gruppen2.domain.model.group.Group;
 import mops.gruppen2.domain.model.group.Type;
 import mops.gruppen2.domain.service.EventStoreService;
@@ -17,7 +19,15 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
+import java.util.stream.Collectors;
 
+/**
+ * Cached alle existierenden Gruppen und einige Beziehungen.
+ * Gruppen können nach Typ angefragt werden, nach ID, nach Link oder nach User.
+ * Der Cache wird von den Events aktualisiert.
+ * Beim Aufruf der init() Methode werden alle bisherigen Events projiziert und die Gruppen gespeichert.
+ * Die Komplette Anwendung verwendet eine Instanz des Caches.
+ */
 @Log4j2
 @RequiredArgsConstructor
 @Component
@@ -28,7 +38,7 @@ public class GroupCache {
 
     private final Map<UUID, Group> groups = new HashMap<>();
     private final Map<String, Group> links = new HashMap<>();
-    private final Map<String, List<Group>> users = new HashMap<>();
+    private final Map<String, List<Group>> users = new HashMap<>(); // Wird vielleicht zu groß?
     private final Map<Type, List<Group>> types = new EnumMap<>(Type.class);
 
 
@@ -59,6 +69,14 @@ public class GroupCache {
         return links.get(link);
     }
 
+    public List<Group> groups() {
+        if (groups.isEmpty()) {
+            return Collections.emptyList();
+        }
+
+        return List.copyOf(groups.values());
+    }
+
     public List<Group> userGroups(String userid) {
         if (!users.containsKey(userid)) {
             return Collections.emptyList();
@@ -67,6 +85,24 @@ public class GroupCache {
         return Collections.unmodifiableList(users.get(userid));
     }
 
+    public List<Group> userLectures(String userid) {
+        return userGroups(userid).stream()
+                                 .filter(Group::isLecture)
+                                 .collect(Collectors.toUnmodifiableList());
+    }
+
+    public List<Group> userPublics(String userid) {
+        return userGroups(userid).stream()
+                                 .filter(Group::isPublic)
+                                 .collect(Collectors.toUnmodifiableList());
+    }
+
+    public List<Group> userPrivates(String userid) {
+        return userGroups(userid).stream()
+                                 .filter(Group::isPrivate)
+                                 .collect(Collectors.toUnmodifiableList());
+    }
+
     public List<Group> publics() {
         if (!types.containsKey(Type.PUBLIC)) {
             return Collections.emptyList();
@@ -96,6 +132,9 @@ public class GroupCache {
 
 
     public void usersPut(String userid, Group group) {
+        if (!group.isMember(userid)) {
+            throw new UserNotFoundException("User ist kein Mitglied, Gruppe nicht gecached.");
+        }
         if (!users.containsKey(userid)) {
             users.put(userid, new ArrayList<>());
             log.debug("Ein User wurde dem Cache hinzugefügt.");
@@ -113,18 +152,37 @@ public class GroupCache {
     }
 
     public void groupsPut(UUID groupid, Group group) {
+        if (group.getId() != groupid) {
+            throw new IdMismatchException("ID passt nicht zu Gruppe, Gruppe nicht gecached.");
+        }
+
         groups.put(groupid, group);
     }
 
-    public void groupsRemove(Group group) {
-        groups.remove(group.getId());
+    public void groupsRemove(UUID groupid, Group group) {
+        if (!groups.containsKey(groupid)) {
+            return;
+        }
+
+        groups.remove(groupid);
+        links.remove(group.getLink());
+        group.getMembers().forEach(user -> users.get(user.getId()).removeIf(usergroup -> !usergroup.exists()));
+        types.get(group.getType()).removeIf(typegroup -> !typegroup.exists());
     }
 
     public void linksPut(String link, Group group) {
+        if (!link.equals(group.getLink())) {
+            throw new IdMismatchException("Link passt nicht zu Gruppe, Gruppe nicht gecached.");
+        }
+
         links.put(link, group);
     }
 
     public void linksRemove(String link) {
+        if (!links.containsKey(link)) {
+            return;
+        }
+
         links.remove(link);
     }
 
@@ -133,15 +191,18 @@ public class GroupCache {
             types.put(type, new ArrayList<>());
             log.debug("Ein Typ wurde dem Cache hinzugefügt.");
         }
+        if (group.getType() != type) {
+            throw new IdMismatchException("Typ passt nicht zu Gruppe, Gruppe nicht gecached.");
+        }
 
         types.get(type).add(group);
     }
 
-    public void typesRemove(Group group) {
-        if (!types.containsKey(group.getType())) {
+    public void typesRemove(Type type, Group group) {
+        if (!types.containsKey(type)) {
             return;
         }
 
-        types.get(group.getType()).remove(group);
+        types.get(type).remove(group);
     }
 }
diff --git a/src/main/java/mops/gruppen2/infrastructure/api/GroupRequestWrapper.java b/src/main/java/mops/gruppen2/infrastructure/api/GroupRequestWrapper.java
index 93a0c20..d2d059d 100644
--- a/src/main/java/mops/gruppen2/infrastructure/api/GroupRequestWrapper.java
+++ b/src/main/java/mops/gruppen2/infrastructure/api/GroupRequestWrapper.java
@@ -1,12 +1,14 @@
 package mops.gruppen2.infrastructure.api;
 
 import lombok.AllArgsConstructor;
+import lombok.Getter;
 
 import java.util.List;
 
 /**
  * Kombiniert den Status und die Gruppenliste zur ausgabe über die API.
  */
+@Getter
 @AllArgsConstructor
 public class GroupRequestWrapper {
 
diff --git a/src/main/java/mops/gruppen2/infrastructure/api/GroupWrapper.java b/src/main/java/mops/gruppen2/infrastructure/api/GroupWrapper.java
index 2fb3fba..75b628d 100644
--- a/src/main/java/mops/gruppen2/infrastructure/api/GroupWrapper.java
+++ b/src/main/java/mops/gruppen2/infrastructure/api/GroupWrapper.java
@@ -1,4 +1,31 @@
 package mops.gruppen2.infrastructure.api;
 
+import lombok.Value;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.Type;
+import mops.gruppen2.domain.model.group.User;
+
+import java.util.List;
+import java.util.UUID;
+
+@Value
 public class GroupWrapper {
+
+    UUID groupid;
+    Type type;
+    UUID parent;
+    String title;
+    String description;
+    List<User> admins;
+    List<User> regulars;
+
+    public GroupWrapper(Group group) {
+        groupid = group.getId();
+        type = group.getType();
+        parent = group.getParent();
+        title = group.getTitle();
+        description = group.getDescription();
+        admins = group.getAdmins();
+        regulars = group.getRegulars();
+    }
 }
diff --git a/src/main/java/mops/gruppen2/infrastructure/controller/APIController.java b/src/main/java/mops/gruppen2/infrastructure/controller/APIController.java
index ac02052..1c79bd2 100644
--- a/src/main/java/mops/gruppen2/infrastructure/controller/APIController.java
+++ b/src/main/java/mops/gruppen2/infrastructure/controller/APIController.java
@@ -1,13 +1,27 @@
 package mops.gruppen2.infrastructure.controller;
 
 
+import io.swagger.annotations.ApiOperation;
+import io.swagger.annotations.ApiParam;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.log4j.Log4j2;
 import mops.gruppen2.aspect.annotation.TraceMethodCalls;
+import mops.gruppen2.domain.model.group.Group;
 import mops.gruppen2.domain.service.EventStoreService;
+import mops.gruppen2.domain.service.helper.APIHelper;
+import mops.gruppen2.domain.service.helper.ProjectionHelper;
+import mops.gruppen2.infrastructure.GroupCache;
+import mops.gruppen2.infrastructure.api.GroupRequestWrapper;
+import org.springframework.security.access.annotation.Secured;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import java.util.List;
+import java.util.UUID;
+import java.util.stream.Collectors;
+
 /**
  * Api zum Datenabgleich.
  */
@@ -18,8 +32,7 @@ import org.springframework.web.bind.annotation.RestController;
 @RequestMapping("/gruppen2/api")
 public class APIController {
 
-    //TODO: redo api
-
+    private final GroupCache cache;
     private final EventStoreService eventStoreService;
 
     /**
@@ -28,38 +41,43 @@ public class APIController {
      *
      * @param eventId Die Event-ID, welche der Anfragesteller beim letzten Aufruf erhalten hat
      */
-    /*@GetMapping("/update/{id}")
+    //TODO: sollte den cache benutzen, am besten wäre eine groupversion, welche der eventid
+    //TODO: entspricht, dann kann man leicht alle geänderten gruppen finden
+    @GetMapping("/update/{id}")
     @Secured("ROLE_api_user")
     @ApiOperation("Gibt veränderte Gruppen zurück")
     public GroupRequestWrapper getApiUpdate(@ApiParam("Letzte gespeicherte EventId des Anfragestellers")
                                             @PathVariable("id") long eventId) {
 
         return APIHelper.wrap(eventStoreService.findMaxEventId(),
-                              projectionHelper.projectChangedGroups(eventId));
-    }*/
+                              ProjectionHelper.project(eventStoreService.findGroupEvents(eventStoreService.findChangedGroups(eventId))));
+    }
 
     /**
      * Gibt die Gruppen-IDs von Gruppen, in welchen der übergebene Nutzer teilnimmt, zurück.
      */
-    /*@GetMapping("/usergroups/{id}")
+    @GetMapping("/usergroups/{id}")
     @Secured("ROLE_api_user")
     @ApiOperation("Gibt Gruppen zurück, in welchen ein Nutzer teilnimmt")
     public List<String> getApiUserGroups(@ApiParam("Nutzer-Id")
                                          @PathVariable("id") String userId) {
 
-        return CommonHelper.uuidsToString(eventStoreService.findExistingUserGroups(userId));
-    }*/
+        return cache.userGroups(userId).stream()
+                    .map(Group::getId)
+                    .map(UUID::toString)
+                    .collect(Collectors.toUnmodifiableList());
+    }
 
     /**
      * Konstruiert eine einzelne, vollständige Gruppe.
      */
-    /*@GetMapping("/group/{id}")
+    @GetMapping("/group/{id}")
     @Secured("ROLE_api_user")
     @ApiOperation("Gibt die Gruppe mit der als Parameter mitgegebenden groupId zurück")
     public Group getApiGroup(@ApiParam("Gruppen-Id der gefordeten Gruppe")
                              @PathVariable("id") String groupId) {
 
-        return projectionHelper.projectGroupById(UUID.fromString(groupId));
-    }*/
+        return cache.group(UUID.fromString(groupId));
+    }
 
 }
diff --git a/src/main/java/mops/gruppen2/infrastructure/controller/GroupCreationController.java b/src/main/java/mops/gruppen2/infrastructure/controller/GroupCreationController.java
index 84d4e1e..60cb879 100644
--- a/src/main/java/mops/gruppen2/infrastructure/controller/GroupCreationController.java
+++ b/src/main/java/mops/gruppen2/infrastructure/controller/GroupCreationController.java
@@ -11,7 +11,7 @@ import mops.gruppen2.domain.model.group.wrapper.Limit;
 import mops.gruppen2.domain.model.group.wrapper.Parent;
 import mops.gruppen2.domain.model.group.wrapper.Title;
 import mops.gruppen2.domain.service.GroupService;
-import mops.gruppen2.domain.service.helper.CsvHelper;
+import mops.gruppen2.domain.service.helper.FileHelper;
 import mops.gruppen2.domain.service.helper.ValidationHelper;
 import mops.gruppen2.infrastructure.GroupCache;
 import org.keycloak.adapters.springsecurity.token.KeycloakAuthenticationToken;
@@ -67,7 +67,7 @@ public class GroupCreationController {
 
         // ROLE_studentin kann kein CSV importieren
         if (token.getAccount().getRoles().contains("orga")) {
-            groupService.addUsersToGroup(group, principal, CsvHelper.readCsvFile(file));
+            groupService.addUsersToGroup(group, principal, FileHelper.readCsvFile(file));
         }
 
         return "redirect:/gruppen2/details/" + group.getId();
diff --git a/src/main/java/mops/gruppen2/infrastructure/controller/GroupDetailsController.java b/src/main/java/mops/gruppen2/infrastructure/controller/GroupDetailsController.java
index 5fffd22..a75abf6 100644
--- a/src/main/java/mops/gruppen2/infrastructure/controller/GroupDetailsController.java
+++ b/src/main/java/mops/gruppen2/infrastructure/controller/GroupDetailsController.java
@@ -8,11 +8,13 @@ import mops.gruppen2.domain.model.group.User;
 import mops.gruppen2.domain.model.group.wrapper.Description;
 import mops.gruppen2.domain.model.group.wrapper.Limit;
 import mops.gruppen2.domain.model.group.wrapper.Title;
+import mops.gruppen2.domain.service.EventStoreService;
 import mops.gruppen2.domain.service.GroupService;
-import mops.gruppen2.domain.service.helper.CsvHelper;
+import mops.gruppen2.domain.service.helper.FileHelper;
 import mops.gruppen2.domain.service.helper.ValidationHelper;
 import mops.gruppen2.infrastructure.GroupCache;
 import org.keycloak.adapters.springsecurity.token.KeycloakAuthenticationToken;
+import org.springframework.http.HttpHeaders;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -24,7 +26,9 @@ import org.springframework.web.multipart.MultipartFile;
 
 import javax.annotation.security.RolesAllowed;
 import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
 import javax.validation.Valid;
+import java.io.IOException;
 import java.util.UUID;
 
 @SuppressWarnings("SameReturnValue")
@@ -37,6 +41,7 @@ public class GroupDetailsController {
 
     private final GroupCache groupCache;
     private final GroupService groupService;
+    private final EventStoreService eventStoreService;
 
     @RolesAllowed({"ROLE_orga", "ROLE_studentin"})
     @GetMapping("/details/{id}")
@@ -94,6 +99,77 @@ public class GroupDetailsController {
         return "redirect:/gruppen2";
     }
 
+    @RolesAllowed({"ROLE_orga", "ROLE_studentin"})
+    @GetMapping("details/{id}/history")
+    public String getDetailsHistory(KeycloakAuthenticationToken token,
+                                    Model model,
+                                    @PathVariable("id") String groupId) {
+
+        model.addAttribute("events",
+                           eventStoreService.findGroupEvents(UUID.fromString(groupId)));
+
+        return "log";
+    }
+
+    @RolesAllowed({"ROLE_orga", "ROLE_studentin"})
+    @GetMapping(value = "details/{id}/export/history/plain", produces = "text/plain;charset=UTF-8")
+    public void getDetailsExportHistoryPlain(HttpServletResponse response,
+                                             @PathVariable("id") String groupId) {
+
+        String filename = "eventlog-" + groupId + ".txt";
+
+        response.setContentType("text/txt;charset=UTF-8");
+        response.setHeader(HttpHeaders.CONTENT_DISPOSITION,
+                           "attachment; filename=\"" + filename + "\"");
+
+        try {
+            response.getWriter()
+                    .write(FileHelper.payloadsToPlain(
+                            eventStoreService.findGroupPayloads(UUID.fromString(groupId))));
+        } catch (IOException e) {
+            log.error("Payloads konnten nicht geschrieben werden.", e);
+        }
+    }
+
+    @RolesAllowed({"ROLE_orga", "ROLE_studentin"})
+    @GetMapping(value = "details/{id}/export/history/sql", produces = "application/sql;charset=UTF-8")
+    public void getDetailsExportHistorySql(HttpServletResponse response,
+                                           @PathVariable("id") String groupId) {
+
+        String filename = "data.sql";
+
+        response.setContentType("application/sql;charset=UTF-8");
+        response.setHeader(HttpHeaders.CONTENT_DISPOSITION,
+                           "attachment; filename=\"" + filename + "\"");
+
+        try {
+            response.getWriter()
+                    .write(FileHelper.eventDTOsToSql(
+                            eventStoreService.findGroupDTOs(UUID.fromString(groupId))));
+        } catch (IOException e) {
+            log.error("Payloads konnten nicht geschrieben werden.", e);
+        }
+    }
+
+    @RolesAllowed({"ROLE_orga", "ROLE_studentin"})
+    @GetMapping(value = "details/{id}/export/members", produces = "text/csv;charset=UTF-8")
+    public void getDetailsExportMembers(HttpServletResponse response,
+                                        @PathVariable("id") String groupId) {
+
+        String filename = "teilnehmer-" + groupId + ".csv";
+
+        response.setContentType("text/csv;charset=UTF-8");
+        response.setHeader(HttpHeaders.CONTENT_DISPOSITION,
+                           "attachment; filename=\"" + filename + "\"");
+
+        try {
+            response.getWriter()
+                    .print(FileHelper.writeCsvUserList(groupCache.group(UUID.fromString(groupId)).getMembers()));
+        } catch (IOException e) {
+            log.error("Teilnehmerliste konnte nicht geschrieben werden.", e);
+        }
+    }
+
     @RolesAllowed({"ROLE_orga", "ROLE_studentin"})
     @GetMapping("/details/{id}/edit")
     public String getDetailsEdit(KeycloakAuthenticationToken token,
@@ -127,8 +203,6 @@ public class GroupDetailsController {
         String principal = token.getName();
         Group group = groupCache.group(UUID.fromString(groupId));
 
-        System.out.println(group);
-
         groupService.setTitle(group, principal, title);
         groupService.setDescription(group, principal, description);
 
@@ -157,7 +231,7 @@ public class GroupDetailsController {
         String principal = token.getName();
         Group group = groupCache.group(UUID.fromString(groupId));
 
-        groupService.addUsersToGroup(group, principal, CsvHelper.readCsvFile(file));
+        groupService.addUsersToGroup(group, principal, FileHelper.readCsvFile(file));
 
         return "redirect:/gruppen2/details/" + groupId + "/edit";
     }
@@ -172,6 +246,9 @@ public class GroupDetailsController {
         Group group = groupCache.group(UUID.fromString(groupId));
 
         ValidationHelper.throwIfNoAdmin(group, principal);
+        if (target.equals(principal)) {
+            ValidationHelper.throwIfLastAdmin(group, principal);
+        }
 
         groupService.toggleMemberRole(group, principal, target);
 
diff --git a/src/main/java/mops/gruppen2/infrastructure/controller/GruppenfindungController.java b/src/main/java/mops/gruppen2/infrastructure/controller/GruppenfindungController.java
index 4d09bdb..2e414ba 100644
--- a/src/main/java/mops/gruppen2/infrastructure/controller/GruppenfindungController.java
+++ b/src/main/java/mops/gruppen2/infrastructure/controller/GruppenfindungController.java
@@ -33,7 +33,10 @@ public class GruppenfindungController {
     @GetMapping("/gruppen2")
     public String getIndexPage(KeycloakAuthenticationToken token,
                                Model model) {
-        model.addAttribute("groups", groupCache.userGroups(token.getName()));
+
+        model.addAttribute("lectures", groupCache.userLectures(token.getName()));
+        model.addAttribute("publics", groupCache.userPublics(token.getName()));
+        model.addAttribute("privates", groupCache.userPrivates(token.getName()));
 
         return "index";
     }
diff --git a/src/main/java/mops/gruppen2/infrastructure/controller/SearchAndInviteController.java b/src/main/java/mops/gruppen2/infrastructure/controller/SearchAndInviteController.java
index 1c96f01..35ae56c 100644
--- a/src/main/java/mops/gruppen2/infrastructure/controller/SearchAndInviteController.java
+++ b/src/main/java/mops/gruppen2/infrastructure/controller/SearchAndInviteController.java
@@ -41,13 +41,40 @@ public class SearchAndInviteController {
     }
 
     @RolesAllowed({"ROLE_orga", "ROLE_studentin"})
-    @PostMapping("/search")
-    public String postSearch(KeycloakAuthenticationToken token,
-                             Model model,
-                             @RequestParam("string") String search) {
+    @PostMapping("/search/string")
+    public String postSearchString(KeycloakAuthenticationToken token,
+                                   Model model,
+                                   @RequestParam("string") String search) {
 
         String principal = token.getName();
-        List<Group> groups = searchService.search(search, principal);
+        List<Group> groups = searchService.searchString(search, principal);
+
+        model.addAttribute("groups", groups);
+
+        return "search";
+    }
+
+    @RolesAllowed({"ROLE_orga", "ROLE_studentin"})
+    @GetMapping("/search/all")
+    public String getSearchAll(KeycloakAuthenticationToken token,
+                               Model model) {
+
+        String principal = token.getName();
+        List<Group> groups = searchService.searchString("", principal);
+
+        model.addAttribute("groups", groups);
+
+        return "search";
+    }
+
+    @RolesAllowed({"ROLE_orga", "ROLE_studentin"})
+    @GetMapping("/search/type/{type}")
+    public String getSearchType(KeycloakAuthenticationToken token,
+                                Model model,
+                                @PathVariable("type") Type type) {
+
+        String principal = token.getName();
+        List<Group> groups = searchService.searchType(type, principal);
 
         model.addAttribute("groups", groups);
 
diff --git a/src/main/java/mops/gruppen2/persistance/EventRepository.java b/src/main/java/mops/gruppen2/persistance/EventRepository.java
index 26a94bb..8d21c79 100644
--- a/src/main/java/mops/gruppen2/persistance/EventRepository.java
+++ b/src/main/java/mops/gruppen2/persistance/EventRepository.java
@@ -3,6 +3,7 @@ package mops.gruppen2.persistance;
 import mops.gruppen2.persistance.dto.EventDTO;
 import org.springframework.data.jdbc.repository.query.Query;
 import org.springframework.data.repository.CrudRepository;
+import org.springframework.data.repository.query.Param;
 import org.springframework.stereotype.Repository;
 
 import java.util.List;
@@ -16,4 +17,16 @@ public interface EventRepository extends CrudRepository<EventDTO, Long> {
 
     @Query("SELECT * FROM event")
     List<EventDTO> findAllEvents();
+
+    @Query("SELECT * FROM event WHERE group_id = :groupid")
+    List<EventDTO> findGroupEvents(@Param("groupid") String groupId);
+
+    @Query("SELECT event_payload FROM event WHERE group_id = :groupid")
+    List<String> findGroupPayloads(@Param("groupid") String groupId);
+
+    @Query("SELECT MAX(event_id) FROM event")
+    long findMaxEventId();
+
+    @Query("SELECT DISTINCT group_id FROM event WHERE event_id > :eventid")
+    List<String> findChangedGroupIds(@Param("eventid") long eventid);
 }
diff --git a/src/main/java/mops/gruppen2/persistance/dto/EventDTO.java b/src/main/java/mops/gruppen2/persistance/dto/EventDTO.java
index d0c326f..c46878a 100644
--- a/src/main/java/mops/gruppen2/persistance/dto/EventDTO.java
+++ b/src/main/java/mops/gruppen2/persistance/dto/EventDTO.java
@@ -5,6 +5,8 @@ import lombok.Getter;
 import org.springframework.data.annotation.Id;
 import org.springframework.data.relational.core.mapping.Table;
 
+import java.sql.Timestamp;
+
 @Table("event")
 @Getter
 @AllArgsConstructor
@@ -19,6 +21,6 @@ public class EventDTO {
     String exec_id;
     String target_id;
 
-    String event_type;
+    Timestamp event_date;
     String event_payload;
 }
diff --git a/src/main/resources/application.properties b/src/main/resources/application.properties
index 45828c0..be154ec 100644
--- a/src/main/resources/application.properties
+++ b/src/main/resources/application.properties
@@ -11,12 +11,12 @@ spring.profiles.active              = dev
 #keycloak.use-resource-role-mappings = true
 #keycloak.autodetect-bearer-only     = true
 #keycloak.confidential-port          = 443
-keycloak.auth-server-url            = https://gruppenkeycloak.herokuapp.com/auth
-hhu_keycloak.token-uri              = https://gruppenkeycloak.herokuapp.com/auth/realms/master/protocol/openid-connect/token
+keycloak.auth-server-url            = https://churl-keycloak.herokuapp.com/auth
+hhu_keycloak.token-uri              = https://churl-keycloak.herokuapp.com/auth/realms/gruppen/protocol/openid-connect/token
 keycloak.principal-attribute        = preferred_username
-keycloak.realm                      = master
+keycloak.realm                      = gruppen
 keycloak.resource                   = gruppen-app
-keycloak.credentials.secret         = f73354fd-614e-4e24-b801-a8d0f4abf531
+keycloak.credentials.secret         = 2e2e5770-c454-4d31-be99-9d8c34c93089
 keycloak.verify-token-audience      = true
 keycloak.use-resource-role-mappings = true
 keycloak.autodetect-bearer-only     = true
diff --git a/src/main/resources/data.sql b/src/main/resources/data.sql
new file mode 100644
index 0000000..45613fb
--- /dev/null
+++ b/src/main/resources/data.sql
@@ -0,0 +1,27 @@
+INSERT INTO event(group_id, group_version, exec_id, target_id, event_date, event_payload)
+VALUES ('e65dd5f1-b252-4512-8db4-0407b31d199f', '1', 'orga', 'null', '2020-04-17 18:52:01.259555',
+        '{"class":"CREATEGROUP","date":[2020,4,17,18,52,1,259555000],"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":1,"exec":"orga","target":null}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '2', 'orga', 'orga', '2020-04-17 18:52:01.291448',
+        '{"class":"ADDMEMBER","user":{"id":"orga","givenname":"Thomas","familyname":"Organisator","email":"orga@hhu.de"},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":2,"exec":"orga","target":"orga","date":[2020,4,17,18,52,1,291448000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '3', 'orga', 'orga', '2020-04-17 18:52:01.301972',
+        '{"class":"UPDATEROLE","role":"ADMIN","groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":3,"exec":"orga","target":"orga","date":[2020,4,17,18,52,1,301972000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '4', 'orga', 'null', '2020-04-17 18:52:01.3053',
+        '{"class":"SETLIMIT","limit":{"value":1000},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":4,"exec":"orga","target":null,"date":[2020,4,17,18,52,1,305300000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '5', 'orga', 'null', '2020-04-17 18:52:01.310406',
+        '{"class":"SETTYPE","type":"LECTURE","groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":5,"exec":"orga","target":null,"date":[2020,4,17,18,52,1,310406000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '6', 'orga', 'null', '2020-04-17 18:52:01.313421',
+        '{"class":"SETPARENT","parent":{"id":"00000000-0000-0000-0000-000000000000"},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":6,"exec":"orga","target":null,"date":[2020,4,17,18,52,1,313421000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '7', 'orga', 'null', '2020-04-17 18:52:01.317931',
+        '{"class":"SETTITLE","title":{"value":"Programmierung SS2020"},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":7,"exec":"orga","target":null,"date":[2020,4,17,18,52,1,317931000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '8', 'orga', 'null', '2020-04-17 18:52:01.320693',
+        '{"class":"SETDESCRIPTION","desc":{"value":"Einführung in die objektorientierte Programmierung mit Java."},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":8,"exec":"orga","target":null,"date":[2020,4,17,18,52,1,320693000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '9', 'orga', 'A5ggd', '2020-04-17 18:52:01.330879',
+        '{"class":"ADDMEMBER","user":{"id":"A5ggd","givenname":"peter","familyname":"pan","email":"peter@pan.com"},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":9,"exec":"orga","target":"A5ggd","date":[2020,4,17,18,52,1,330879000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '10', 'orga', 'Affs', '2020-04-17 18:52:01.333756',
+        '{"class":"ADDMEMBER","user":{"id":"Affs","givenname":"olaf","familyname":"pomodoro","email":"ol@f-99.de"},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":10,"exec":"orga","target":"Affs","date":[2020,4,17,18,52,1,333756000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '11', 'orga', '55fdd', '2020-04-17 18:52:01.336206',
+        '{"class":"ADDMEMBER","user":{"id":"55fdd","givenname":"dieter","familyname":"niemöller","email":"pfarrer@erde.de"},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":11,"exec":"orga","target":"55fdd","date":[2020,4,17,18,52,1,336206000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '12', 'orga', '22ööl', '2020-04-17 18:52:01.338582',
+        '{"class":"ADDMEMBER","user":{"id":"22ööl","givenname":"thomas","familyname":"müller","email":"thot@scheisse.de"},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":12,"exec":"orga","target":"22ööl","date":[2020,4,17,18,52,1,338582000]}'),
+       ('e65dd5f1-b252-4512-8db4-0407b31d199f', '13', 'orga', 'tdsd8', '2020-04-17 18:52:01.341216',
+        '{"class":"ADDMEMBER","user":{"id":"tdsd8","givenname":"tobidignouserandingdong","familyname":"abraham","email":"g@gmail.mail"},"groupid":"e65dd5f1-b252-4512-8db4-0407b31d199f","version":13,"exec":"orga","target":"tdsd8","date":[2020,4,17,18,52,1,341216000]}');
diff --git a/src/main/resources/schema-h2.sql b/src/main/resources/schema-h2.sql
index 46b52a7..0f2779a 100644
--- a/src/main/resources/schema-h2.sql
+++ b/src/main/resources/schema-h2.sql
@@ -7,6 +7,6 @@ CREATE TABLE event
     group_version INT           NOT NULL,
     exec_id       VARCHAR(50)   NOT NULL,
     target_id     VARCHAR(50),
-    event_type    VARCHAR(32)   NOT NULL,
+    event_date    DATETIME      NOT NULL,
     event_payload VARCHAR(2500) NOT NULL
 );
diff --git a/src/main/resources/static/css/details.css b/src/main/resources/static/css/details.css
index ac5b9bf..1df08cc 100644
--- a/src/main/resources/static/css/details.css
+++ b/src/main/resources/static/css/details.css
@@ -3,34 +3,15 @@
     margin-bottom: 15px;
 }
 
-/*Buttons*/
-.edit {
-    font-size: 20px;
-}
-
-.btn-bar {
-    align-self: start;
-}
-
-/*Badges*/
-.badge-pill {
-    align-self: start;
-    margin-right: 10px;
-}
-
-.members .badge {
-    align-self: start;
-    margin-top: 2px;
-}
-
 /*Member List*/
 .members {
     overflow-y: auto;
+    overflow-x: hidden;
     max-height: calc(100vh - 250px);
+    max-width: 100%;
 }
 
-.members li span {
+li span {
     text-overflow: ellipsis;
     overflow: hidden;
-    white-space: nowrap;
 }
diff --git a/src/main/resources/static/css/index.css b/src/main/resources/static/css/index.css
index a68447b..08993cb 100644
--- a/src/main/resources/static/css/index.css
+++ b/src/main/resources/static/css/index.css
@@ -1,19 +1,16 @@
 /*Grouplist Hover Effect*/
 .content {
-    padding-right: 20px;
     background: #e6f4ff;
     box-shadow: 0 .125rem .25rem rgba(0, 0, 0, .075);
 }
 
 .content:hover {
-    padding-right: 10px;
     background: #d4ecff;
     box-shadow: 0 .125rem .25rem rgba(0, 0, 0, .25);
 }
 
 .content:hover .content-heading {
     padding-bottom: 10px;
-    padding-left: 10px;
 }
 
 .content-text-in {
@@ -26,6 +23,5 @@
 
 /*Badges*/
 .badge-pill {
-    margin-left: 10px;
-    align-self: start;
+    margin-right: 15px;
 }
diff --git a/src/main/resources/static/css/search.css b/src/main/resources/static/css/search.css
index 7195bb3..eed7426 100644
--- a/src/main/resources/static/css/search.css
+++ b/src/main/resources/static/css/search.css
@@ -23,5 +23,5 @@
 .badge-pill {
     align-self: start;
     margin-top: 2px;
-    margin-right: 5px;
+    margin-right: 15px;
 }
diff --git a/src/main/resources/static/css/style.css b/src/main/resources/static/css/style.css
index 9ca338f..dab0b4a 100644
--- a/src/main/resources/static/css/style.css
+++ b/src/main/resources/static/css/style.css
@@ -16,6 +16,9 @@
     margin-bottom: 15px;
     box-shadow: 0 .125rem .25rem rgba(0, 0, 0, .25);
     transition: 100ms;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    cursor: default;
 }
 
 /*Content Heading*/
@@ -33,6 +36,12 @@
     white-space: nowrap;
 }
 
+h1, h3 {
+    cursor: default;
+    overflow: hidden;
+    text-overflow: ellipsis;
+}
+
 /*Content Paragraph*/
 .content-text {
     margin-bottom: 15px;
@@ -65,10 +74,19 @@
     color: #4fa4ff;
 }
 
+/*Button*/
+.btn {
+    width: 250px;
+}
+
+.btn-spacer {
+}
+
 /*Badges*/
 .badge-pill {
     cursor: default;
     color: whitesmoke;
+    align-self: start;
 }
 
 .lecture {
@@ -87,18 +105,31 @@
     background: var(--warning);
 }
 
-/*Grid System*/
-.row {
-    margin-left: 0;
-    margin-right: 0;
+/*Input*/
+.input-group {
+    width: auto;
 }
 
-.col {
-    padding-left: 0;
-    padding-right: 0;
+.input-group-append {
+    max-width: 50%;
+    overflow: hidden;
+    text-overflow: ellipsis;
 }
 
-/*Miscellanous*/
-.def-cursor {
-    cursor: default;
+.input-group-append {
+    max-width: 50%;
+    overflow: hidden;
+    text-overflow: ellipsis;
+}
+
+.input-group-append span {
+    overflow: hidden;
+    text-overflow: ellipsis;
+    font-family: monospace;
+}
+
+.input-group-append span {
+    overflow: hidden;
+    text-overflow: ellipsis;
+    font-family: monospace;
 }
diff --git a/src/main/resources/templates/create.html b/src/main/resources/templates/create.html
index b2f4c21..8c0d28b 100644
--- a/src/main/resources/templates/create.html
+++ b/src/main/resources/templates/create.html
@@ -9,37 +9,35 @@
 <body>
 
 <main th:fragment="bodycontent">
-    <div class="container">
+    <h1>Neue Gruppe</h1>
 
-        <h1 class="def-cursor">Neue Gruppe</h1>
+    <form enctype="multipart/form-data" method="post" th:action="@{/gruppen2/create}">
+        <div class="content px-1 px-sm-3 mx-n2 mx-sm-0">
+            <h3>Eigenschaften:</h3>
 
-        <form enctype="multipart/form-data" method="post" th:action="@{/gruppen2/create}">
-            <div class="content">
-                <h3 class="def-cursor">Eigenschaften:</h3>
+            <!--Titel + Beschreibung-->
+            <div class="content-text" th:insert="~{fragments/forms :: meta}"></div>
 
-                <!--Titel + Beschreibung-->
-                <div class="content-text" th:insert="~{fragments/forms :: meta}"></div>
+            <!--TODO: Enter AsciiDoc Description-->
 
-                <!--TODO: Enter AsciiDoc Description-->
+            <div class="content-text-in">
+                <!--Gruppentyp-->
+                <div th:insert="~{fragments/forms :: grouptype}"></div>
 
-                <div class="content-text-in">
-                    <!--Gruppentyp-->
-                    <div th:replace="~{fragments/forms :: grouptype}"></div>
-
-                    <!--Benutzerlimit-->
-                    <div th:replace="~{fragments/forms :: userlimit}"></div>
-                </div>
-
-                <!--CSV Import-->
-                <div class="content-text mb-0" th:insert="~{fragments/forms :: csvimport}"></div>
+                <!--Benutzerlimit-->
+                <div class="mt-2" th:insert="~{fragments/forms :: userlimit}"></div>
             </div>
 
-            <div class="content">
-                <!--Submit-->
-                <button class="btn btn-primary btn-block" type="submit">Gruppe Erstellen</button>
-            </div>
-        </form>
-    </div>
+            <!--CSV Import-->
+            <div class="content-text mb-0" th:insert="~{fragments/forms :: csvimport}"></div>
+        </div>
+
+        <div class="content d-flex flex-row flex-wrap px-1 px-sm-3">
+            <!--Submit-->
+            <button class="btn btn-primary btn-block ml-auto" type="submit">Gruppe Erstellen
+            </button>
+        </div>
+    </form>
 </main>
 
 </body>
diff --git a/src/main/resources/templates/details.html b/src/main/resources/templates/details.html
index aa64206..0a4a400 100644
--- a/src/main/resources/templates/details.html
+++ b/src/main/resources/templates/details.html
@@ -9,60 +9,198 @@
 <body>
 
 <main th:fragment="bodycontent">
-    <div class="container-fluid">
+    <h1 th:text="${group.getTitle()}"></h1>
 
-        <h1 class="def-cursor" th:text="${group.getTitle()}"></h1>
+    <div class="d-flex flex-row flex-wrap mr-n4 mt-n2">
+        <!--Gruppendetails-->
+        <div class="flex-grow-1 mr-4 mt-2" style="flex-basis: 65%;">
 
-        <div class="row">
-            <!--Gruppendetails-->
-            <div class="col-9 px-0">
+            <div class="content py-2 px-1 px-sm-3 mx-n2 mx-sm-0"
+                 th:insert="~{fragments/groups :: groupcontent}"></div>
 
-                <div class="content" th:insert="~{fragments/groups :: groupcontent}"></div>
 
-                <div class="content">
-                    <!--Button-Bar-->
-                    <div class="row">
-                        <a class="btn btn-primary" href="/gruppen2">Fertig</a>
+            <!--Dummy Integrationen, der Inhalt kommt natürlich aus der Gruppe bzw. von anderen Systemen-->
+            <div class="d-flex flex-row flex-wrap mr-n2 mt-n2">
+                <!--Materialsammlung-->
+                <div th:if="${group.hasMaterial()}" class="content flex-grow-1 mr-2 mt-2 py-2 px-1 px-sm-3">
+                    <div class="content-heading">
+                        <span>Gruppenmaterialien</span>
+                    </div>
 
-                        <!--Spacer-->
-                        <span class="col"></span>
+                    <div class="content-text-in">
+                        <h3>Neue Materialien:</h3>
+                        <ul>
+                            <li><a href="/">Blatt 3.pdf</a></li>
+                            <li><a href="/">Vorlesung 5.pdf</a></li>
+                            <li><a href="/">Wikipedia.de/blabla</a></li>
+                        </ul>
+                        <h3>Angepinnt:</h3>
+                        <ul>
+                            <li><a href="/">Sicherheitsregeln.pdf</a></li>
+                            <li><a href="/">Bewertungskriterien.pdf</a></li>
+                        </ul>
+                    </div>
+                    <div class="content-text d-flex flex-row flex-wrap mt-n2 mr-n2">
+                        <a class="btn btn-success flex-grow-1 mt-2 mr-2" href="/">Neuer
+                                                                                  Upload.</a>
+                        <a class="btn btn-info ml-auto flex-grow-1 mt-2 mr-2" href="/">
+                            Zur Materialsammlung.</a>
+                    </div>
+                </div>
 
+                <!--Foren-->
+                <div th:if="${group.hasForums()}" class="content flex-grow-1 mr-2 mt-2 py-2 px-1 px-sm-3">
+                    <div class="content-heading">
+                        <span>Forum</span>
+                    </div>
+
+                    <div class="content-text-in">
+                        <h3>Letzte Aktivität:</h3>
+                        <ul>
+                            <li><a href="/">"Re: Ey schick lösung"</a></li>
+                            <li><a href="/">"Re: Aufgabe 2"</a></li>
+                            <li><a href="/">"Neu: Ankündigung"</a></li>
+                        </ul>
+                    </div>
+
+                    <div class="content-text d-flex flex-row flex-wrap mt-n2 mr-n2">
+                        <a class="btn btn-success flex-grow-1 mt-2 mr-2" href="/">
+                            Frage stellen.</a>
+                        <a class="btn btn-info flex-grow-1 ml-auto mt-2 mr-2" href="/">
+                            Zum Forum.</a>
+                    </div>
+                </div>
+
+                <!--Termine-->
+                <div th:if="${group.hasCalendar()}" class="content flex-grow-1 mr-2 mt-2 py-2 px-1 px-sm-3">
+                    <div class="content-heading">
+                        <span>Gruppentermine</span>
+                    </div>
+
+                    <div class="content-text-in">
+                        <h3>Nächste Fristen:</h3>
+                        <ul>
+                            <li><a href="/">"Abgabe Übungsblatt 3"</a></li>
+                            <li><a href="/">"Feedback VL 5"</a></li>
+                            <li><a href="/">"Übungsgruppe belegen"</a></li>
+                        </ul>
+                    </div>
+
+                    <div class="content-text d-flex flex-row flex-wrap mt-n2 mr-n2">
+                        <a class="btn btn-success flex-grow-1 mt-2 mr-2" href="/">
+                            Abstimmung starten.</a>
+                        <a class="btn btn-info flex-grow-1 ml-auto mt-2 mr-2" href="/">
+                            Zur Terminfindung.</a>
+                    </div>
+                </div>
+
+                <!--Portfolios-->
+                <div th:if="${group.hasPortfolios()}" class="content flex-grow-1 mr-2 mt-2 py-2 px-1 px-sm-3">
+                    <div class="content-heading">
+                        <span>Gruppenportfolio</span>
+                    </div>
+
+                    <div class="content-text-in">
+                        <h3>Neueste Einträge:</h3>
+                        <ul>
+                            <li><a href="/">"Praktikum Tag 5"</a></li>
+                            <li><a href="/">"Praktikum Tag 4"</a></li>
+                            <li><a href="/">"Nacharbeit Tag 3"</a></li>
+                        </ul>
+                    </div>
+
+                    <div class="content-text d-flex flex-row flex-wrap mt-n2 mr-n2">
+                        <a class="btn btn-success flex-grow-1 mt-2 mr-2" href="/">
+                            Neue Seite.</a>
+                        <a class="btn btn-info flex-grow-1 ml-auto mt-2 mr-2" href="/">
+                            Zum Portfolio.</a>
+                    </div>
+                </div>
+
+                <!--Modulhandbuch-->
+                <div th:if="${group.hasModules()}" class="content flex-grow-1 mr-2 mt-2 py-2 px-1 px-sm-3">
+                    <div class="content-heading">
+                        <span>Modulhandbuch</span>
+                    </div>
+
+                    <div class="content-text-in">
+                        <h3>Veranstaltungsinfo:</h3>
+                        <p>
+                            Dieses Modul vermittelt grundlegende Programmierkenntnisse in einer
+                            objektorientierten Programmiersprache.
+                            Darüber hinaus werden einführend Aspekte von Algorithmen und
+                            Datenstrukturen behandelt.
+                            Es wird keine Programmiererfahrung vorausgesetzt.
+                        </p>
+                        <ul>
+                            <li>Grundlegende Begriffe der Informatik</li>
+                            <li>Primitive Datentypen und Variablen</li>
+                            <li>Kontrollstrukturen</li>
+                            <li>Eigene Datentypen (Klassen) und Arrays</li>
+                            <li>Programmstrukturen im Speicher (Heap, Stack)</li>
+                            <li>Konzepte der Objektorientierung (Polymorphie, Schnittstellen)
+                            </li>
+                            <li>Rekursion</li>
+                            <li>Fehlerbehandlung</li>
+                            <li>Dynamische Datenstrukturen (Listen, Binärbäume, Hashing)</li>
+                            <li>Suchen und Sortieren (ausgewählte Algorithmen, u.a. binäre
+                                Suche, BubbleSort, QuickSort)
+                            </li>
+                            <li>Datenströme (Standard-Eingabe und -Ausgabe, einfache 2D-Grafik,
+                                Dateien)
+                            </li>
+                        </ul>
+                    </div>
+
+                    <div class="content-text d-flex flex-row flex-wrap mt-n2 mr-n2">
+                        <a class="btn btn-info flex-grow-1 ml-auto mt-2 mr-2" href="/">
+                            Zum Modulhandbuch.</a>
+                    </div>
+                </div>
+            </div>
+
+            <div class="content py-2 px-1 px-sm-3">
+                <!--Button-Bar-->
+                <div class="d-flex flex-row flex-wrap mr-n2 mt-n2">
+                    <a class="btn btn-primary flex-grow-1 mr-2 mt-2" href="/gruppen2">Fertig</a>
+
+                    <div class="ml-auto mr-2 mt-2 flex-grow-1 btn-spacer ml-auto">
                         <form method="post" th:action="@{/gruppen2/details/{id}/leave(id=${group.getId()})}">
-                            <button class="btn btn-danger btn-bar" type="submit">Gruppe verlassen
+                            <button class="btn btn-danger w-100" type="submit">
+                                Gruppe verlassen
                             </button>
                         </form>
                     </div>
                 </div>
             </div>
+        </div>
 
-            <!--Teilnehmerliste-->
-            <div class="col-3 def-cursor">
-                <!--Anzahl Text-->
-                <div class="mb-2">
-                    <span>Teilnehmer: </span>
-                    <span th:text="${group.size() + ' von ' + group.getLimit()}"></span>
-                </div>
-
-                <!--Bearbeiten-Button-->
-                <div class="mb-2" th:if="${group.isAdmin(principal.getId())}">
-                    <form method="get"
-                          th:action="@{/gruppen2/details/{id}/edit(id=${group.getId()})}">
-                        <button class="btn btn-secondary btn-block">Gruppe verwalten</button>
-                    </form>
-                </div>
-
-                <!--Liste-->
-                <div class="members">
-                    <ul class="list-group">
-                        <li class="list-group-item d-flex justify-content-between"
-                            th:each="member : ${group.getMembers()}">
-                            <span th:text="${member.format()}"></span>
-                            <span th:replace="~{fragments/groups :: userbadges}"></span>
-                        </li>
-                    </ul>
-                </div>
+        <!--Teilnehmerliste-->
+        <div class="def-cursor flex-grow-1 mr-4 mt-2 mw-100 overflow-hidden py-2 px-1 px-sm-3">
+            <!--Anzahl Text-->
+            <div class="mb-2">
+                <span>Teilnehmer: </span>
+                <span th:text="${group.size() + ' von ' + group.getLimit()}"></span>
             </div>
 
+            <!--Bearbeiten-Button-->
+            <div class="mb-2" th:if="${group.isAdmin(principal.getId())}">
+                <form method="get"
+                      th:action="@{/gruppen2/details/{id}/edit(id=${group.getId()})}">
+                    <button class="btn btn-secondary btn-block">Gruppe verwalten</button>
+                </form>
+            </div>
+
+            <!--Liste-->
+            <div class="members">
+                <ul class="list-group">
+                    <li class="list-group-item d-flex justify-content-between"
+                        th:each="member : ${group.getMembers()}">
+                        <span th:text="${member.format()}"></span>
+                        <span th:replace="~{fragments/groups :: userbadges}"></span>
+                    </li>
+                </ul>
+            </div>
         </div>
     </div>
 </main>
diff --git a/src/main/resources/templates/edit.html b/src/main/resources/templates/edit.html
index e65cbdb..0756e05 100644
--- a/src/main/resources/templates/edit.html
+++ b/src/main/resources/templates/edit.html
@@ -9,113 +9,148 @@
 <body>
 
 <main th:fragment="bodycontent">
-    <div class="container-fluid">
-        <h1 class="def-cursor" th:text="${group.getTitle()}"></h1>
+    <h1 th:text="${group.getTitle()}"></h1>
 
-        <!--Fertig oder löschen-->
-        <div class="content">
-            <div class="row">
-                <form method="get" th:action="@{/gruppen2/details/{id}(id=${group.getId()})}">
-                    <button class="btn btn-primary">Fertig</button>
-                </form>
-
-                <!--Spacer-->
-                <span class="col"></span>
+    <!--Fertig oder löschen-->
+    <div class="content py-2 px-1 px-sm-3 mx-n2 mx-sm-0">
+        <div class="d-flex flex-row flex-wrap mt-n2 mr-n2">
+            <a class="btn btn-primary flex-grow-1 mt-2 mr-2" style="max-width: 250px;"
+               th:href="@{/gruppen2/details/{id}(id=${group.getId()})}">Fertig</a>
 
+            <div class="mt-2 mr-2 flex-grow-1 ml-auto btn-spacer">
                 <form method="post" th:action="@{/gruppen2/details/{id}/edit/destroy(id=${group.getId()})}">
-                    <button class="btn btn-danger btn-bar" type="submit">Gruppe löschen
+                    <button class="btn btn-danger w-100" type="submit">Gruppe löschen
                     </button>
                 </form>
             </div>
         </div>
+    </div>
 
-        <!--Invite Link-->
-        <div class="content input-group">
-            <div class="input-group-prepend">
-                <span class="input-group-text">Einladungslink:</span>
-            </div>
-            <input class="form-control" id="linkview" readonly th:value="${link}" type="text">
-            <div class="input-group-append">
-                <button type="button" class="btn btn-secondary"
-                        onclick="copyLink()">Link kopieren
-                </button>
-            </div>
+    <!--Invite Link-->
+    <div class="content input-group py-2 px-1 px-sm-3 mx-n2 mx-sm-0">
+        <div class="input-group-prepend">
+            <span class="input-group-text">Einladungslink:</span>
         </div>
-
-        <!--Meta-->
-        <div class="content">
-            <div class="content-heading">
-                <span>Eigenschaften</span>
-            </div>
-
-            <!--Beschreibung + Titel-->
-            <div class="content-text">
-                <form th:action="@{/gruppen2/details/{id}/edit/meta(id=${group.getId()})}"
-                      method="post">
-
-                    <div th:replace="~{fragments/forms :: meta}"></div>
-                    <div class="row">
-                        <span class="col"></span>
-                        <button type="submit" class="btn btn-secondary mt-2">Speichern</button>
-                    </div>
-                </form>
-            </div>
-
-            <!--Userlimit-->
-            <div class="content-text-in">
-                <form th:action="@{/gruppen2/details/{id}/edit/userlimit(id=${group.getId()})}"
-                      method="post">
-
-                    <div th:replace="~{fragments/forms :: userlimit}"></div>
-                    <div class="row">
-                        <span class="col"></span>
-                        <button type="submit" class="btn btn-secondary mt-2">Speichern</button>
-                    </div>
-                </form>
-            </div>
-
-            <!--CSV Import-->
-            <div class="content-text mb-0">
-                <form th:action="@{/gruppen2/details/{id}/edit/csv(id=${group.getId()})}"
-                      th:if="${account.getRoles().contains('orga')}"
-                      enctype="multipart/form-data" method="post">
-
-                    <div th:replace="~{fragments/forms :: csvimport}"></div>
-                    <div class="row">
-                        <span class="col"></span>
-                        <button type="submit" class="btn btn-secondary mt-2">Speichern</button>
-                    </div>
-                </form>
-            </div>
-        </div>
-
-        <!--Teilnehmerliste-->
-        <div class="content members">
-            <div class="content-heading">
-                <span>Teilnehmer</span>
-            </div>
-
-            <ul class="list-group">
-                <li class="list-group-item d-flex justify-content-between" th:each="member : ${group.getMembers()}">
-                    <div>
-                        <span th:text="${member.format()}"></span>
-                        <span th:replace="~{fragments/groups :: userbadges}"></span>
-                    </div>
-
-                    <div class="d-flex">
-                        <form th:action="@{/gruppen2/details/{id}/edit/delete/{userid}(id=${group.getId()}, userid=${member.getId()})}"
-                              th:unless="${member.getId() == account.getName()}"
-                              method="post">
-                            <button type="submit" class="btn btn-danger mr-2">Entfernen</button>
-                        </form>
-
-                        <form th:action="@{/gruppen2/details/{id}/edit/role/{userid}(id=${group.getId()}, userid=${member.getId()})}"
-                              method="post">
-                            <button type="submit" class="btn btn-warning">Rolle ändern</button>
-                        </form>
-                    </div>
-                </li>
-            </ul>
+        <input class="form-control" id="linkview" readonly th:value="${link}" type="text">
+        <div class="input-group-append">
+            <button type="button" class="btn btn-secondary" onclick="copyLink()">Link kopieren
+            </button>
         </div>
     </div>
+
+    <!--Meta-->
+    <div class="content py-2 px-1 px-sm-3 mx-n2 mx-sm-0">
+        <div class="content-heading">
+            <span>Eigenschaften</span>
+        </div>
+
+        <!--Beschreibung + Titel-->
+        <div class="content-text">
+            <form th:action="@{/gruppen2/details/{id}/edit/meta(id=${group.getId()})}"
+                  method="post">
+
+                <div th:replace="~{fragments/forms :: meta}"></div>
+
+                <div class="d-flex flex-row flex-wrap">
+                    <button type="submit" class="btn btn-secondary mt-2 ml-auto">Speichern
+                    </button>
+                </div>
+            </form>
+        </div>
+
+        <!--Userlimit-->
+        <div class="content-text-in px-1 px-sm-3">
+            <form th:action="@{/gruppen2/details/{id}/edit/userlimit(id=${group.getId()})}"
+                  method="post">
+
+                <div th:replace="~{fragments/forms :: userlimit}"></div>
+
+                <div class="d-flex flex-row flex-wrap">
+                    <button type="submit" class="btn btn-secondary mt-2 ml-auto">Speichern
+                    </button>
+                </div>
+            </form>
+        </div>
+
+        <!--CSV Import-->
+        <div class="content-text mb-0">
+            <form th:action="@{/gruppen2/details/{id}/edit/csv(id=${group.getId()})}"
+                  th:if="${account.getRoles().contains('orga')}"
+                  enctype="multipart/form-data" method="post">
+
+                <div th:replace="~{fragments/forms :: csvimport}"></div>
+
+                <div class="d-flex flex-row flex-wrap">
+                    <button type="submit" class="btn btn-secondary mt-2 ml-auto">Speichern
+                    </button>
+                </div>
+            </form>
+        </div>
+    </div>
+
+    <!--Export + Log-->
+    <div class="content py-2 px-1 px-sm-3 mx-n2 mx-sm-0">
+        <div class="content-heading">
+            <span>Event-Historie</span>
+        </div>
+        <div class="d-flex flex-row flex-wrap mt-n2 mr-n2">
+            <a class="btn btn-primary mt-2 mr-2 flex-grow-1"
+               th:href="@{/gruppen2/details/{id}/history(id=${group.getId()})}">Event-Log</a>
+
+            <a class="btn btn-info flex-grow-1 mt-2 mr-2 ml-auto"
+               th:href="@{/gruppen2/details/{id}/export/history/plain(id=${group.getId()})}"
+               title="Exportiert die gesamte Event-Historie dieser Gruppe. Kann beim erstellen importiert werden.">
+                Event-Log exportieren (TXT)
+            </a>
+
+            <a class="btn btn-info flex-grow-1 mt-2 mr-2"
+               th:href="@{/gruppen2/details/{id}/export/history/sql(id=${group.getId()})}"
+               title="Exportiert die gesamte Event-Historie dieser Gruppe. Kann als data.sql verwendet werden.">
+                Event-Log exportieren (SQL)
+            </a>
+
+            <a class="btn btn-info flex-grow-1 mt-2 mr-2"
+               th:href="@{/gruppen2/details/{id}/export/members(id=${group.getId()})}"
+               title="Exportiert die Teilnehmerliste. Kann beim erstellen (oder nachträglich) importiert werden.">
+                Teilnehmer exportieren
+            </a>
+        </div>
+    </div>
+
+    <!--Teilnehmerliste-->
+    <div class="content members py-2 px-1 px-sm-3 mx-n2 mx-sm-0">
+        <div class="content-heading">
+            <span>Teilnehmer</span>
+        </div>
+
+        <ul class="list-group">
+            <li class="list-group-item d-flex flex-row flex-wrap" th:each="member : ${group.getMembers()}">
+                <div class="overflow-hidden ml-n2" style="max-width: 50%; text-overflow: ellipsis;">
+                    <span class="overflow-hidden ml-2" th:text="${member.format()}"></span>
+                    <span th:replace="~{fragments/groups :: userbadges}"></span>
+                </div>
+
+                <div class="d-flex flex-row flex-wrap mt-n2 mr-n2 ml-auto" style="max-width: 50%;">
+                    <div class="flex-grow-1 mt-2 mr-2"
+                         th:unless="${member.getId() == account.getName()}">
+                        <form th:action="@{/gruppen2/details/{id}/edit/delete/{userid}(id=${group.getId()}, userid=${member.getId()})}"
+                              method="post">
+                            <button type="submit" class="btn btn-danger w-100">
+                                Entfernen
+                            </button>
+                        </form>
+                    </div>
+
+                    <div class="flex-grow-1 mt-2 mr-2">
+                        <form th:action="@{/gruppen2/details/{id}/edit/role/{userid}(id=${group.getId()}, userid=${member.getId()})}"
+                              method="post">
+                            <button type="submit" class="btn btn-warning w-100">
+                                Rolle ändern
+                            </button>
+                        </form>
+                    </div>
+                </div>
+            </li>
+        </ul>
+    </div>
 </main>
diff --git a/src/main/resources/templates/error.html b/src/main/resources/templates/error.html
index c77a090..a2c3274 100644
--- a/src/main/resources/templates/error.html
+++ b/src/main/resources/templates/error.html
@@ -12,7 +12,7 @@
 <main th:fragment="bodycontent">
     <div class="container">
 
-        <h1 class="display-3 def-cursor">UPSI</h1>
+        <h1 class="display-3">UPSI</h1>
 
         <div class="content">
             <p class="lead def-cursor">Da ist wohl etwas schiefgelaufen :(</p>
diff --git a/src/main/resources/templates/fragments/forms.html b/src/main/resources/templates/fragments/forms.html
index f38f3bc..17607d7 100644
--- a/src/main/resources/templates/fragments/forms.html
+++ b/src/main/resources/templates/fragments/forms.html
@@ -13,7 +13,7 @@
     <div class="input-group mb-2"
          title="Ein Gruppentitel zwischen 4 und 128 Zeichen. Der Titel ist öffentlich.">
         <div class="input-group-prepend">
-            <span class="input-group-text text-monospace">Gruppentitel:</span>
+            <span class="input-group-text">Gruppentitel:</span>
         </div>
         <input type="text" class="form-control" name="title" minlength="4" maxlength="128"
                th:value="${group?.getTitle()}" required>
@@ -24,7 +24,7 @@
     <div class="input-group"
          title="Eine kurze Gruppenbeschreibung zwischen 4 und 512 Zeichen. Die Beschreibung ist öffentlich.">
         <div class="input-group-prepend">
-            <span class="input-group-text text-monospace">Beschreibung:</span>
+            <span class="input-group-text">Beschreibung:</span>
         </div>
         <textarea class="form-control" name="description" minlength="4" maxlength="512"
                   th:text="${group?.getDescription()}" required></textarea>
@@ -34,8 +34,8 @@
 <!--Gruppentyp-->
 <th:block th:fragment="grouptype">
     <label for="grouptype">Gruppentyp:</label>
-    <div class="btn-toolbar row mb-2 mx-0" id="grouptype">
-        <div class="btn-group btn-group-toggle col-sm-4 px-0" data-toggle="buttons">
+    <div class="btn-toolbar mt-n2 mr-n2 d-flex flex-row flex-wrap overflow-hidden" id="grouptype">
+        <div class="btn-group btn-group-toggle flex-grow-1 mt-2 mr-2" style="flex-basis: 10%;" data-toggle="buttons">
             <label class="btn btn-secondary active" onclick="enable('#parentselect'); disable('#parentdummy')">
                 <input type="radio" name="type" value="PRIVATE" checked> Privat
             </label>
@@ -48,10 +48,10 @@
             </label>
         </div>
 
-        <div class="input-group col-sm-8 pr-0"
+        <div class="input-group flex-grow-1 mt-2 mr-2"
              title="Optional kann eine Veranstaltungszugehörigkeit festgelegt werden.">
             <div class="input-group-prepend">
-                <span class="input-group-text text-monospace">Gehört zu:</span>
+                <span class="input-group-text">Gehört zu:</span>
             </div>
             <input type="hidden" id="parentdummy" name="parent" value="00000000-0000-0000-0000-000000000000" disabled>
             <select class="custom-select" id="parentselect" name="parent">
@@ -66,10 +66,10 @@
 <!--Userlimit-->
 <th:block th:fragment="userlimit">
     <label for="userlimit">Teilnehmeranzahl:</label>
-    <div class="btn-toolbar row mx-0" id="userlimit">
+    <div class="btn-toolbar mt-n2 mr-n2 d-flex flex-row flex-wrap flex-grow-1" id="userlimit">
         <input type="hidden" name="limit" id="limit" value="999999"
                th:disabled="${group != null && group.getLimit() < 999999} ? 'disabled' : 'false'">
-        <div class="btn-group btn-group-toggle col-sm-4 px-0" data-toggle="buttons">
+        <div class="btn-group btn-group-toggle flex-grow-1 mt-2 mr-2" style="flex-basis: 10%;" data-toggle="buttons">
             <label class="btn btn-secondary active" onclick="disable('#limitselect'); enable('#limit')">
                 <input type="radio"
                        th:checked="${group != null && group.getLimit() < 999999} ? 'false' : 'checked'">
@@ -82,17 +82,17 @@
             </label>
         </div>
 
-        <div class="input-group col-sm-8 pr-0"
+        <div class="input-group flex-grow-1 mt-2 mr-2"
              title="999999 ist die maximal zulässige Teilnehmerzahl. Ist diese Obergrenze erreicht, gilt die Gruppe als unbegrenzt.">
-            <div class="input-group-prepend">
-                <span class="input-group-text text-monospace">Limit:</span>
+            <div class="input-group-prepend" style="max-width: 25%">
+                <span class="input-group-text">Limit:</span>
             </div>
             <input type="number" class="form-control" name="limit"
                    th:value="${group != null} ? ${group.getLimit()} : '999999'"
                    min="1" max="999999" id="limitselect" required
                    th:disabled="${group != null && group.getLimit() < 999999} ? 'false' : 'disabled'">
-            <div class="input-group-append">
-                <span class="input-group-text text-monospace">Teilnehmer</span>
+            <div class="input-group-append" style="max-width: 25%">
+                <span class="input-group-text">Teilnehmer</span>
             </div>
         </div>
     </div>
@@ -102,7 +102,7 @@
 <div th:fragment="csvimport" class="input-group" th:if="${account.getRoles().contains('orga')}"
      title="Das CSV folgt dem Format id,givenname,familyname,email.">
     <div class="input-group-prepend">
-        <span class="input-group-text text-monospace">CSV:</span>
+        <span class="input-group-text">CSV:</span>
     </div>
     <div class="custom-file">
         <input type="file" class="custom-file-input" id="file" name="file">
diff --git a/src/main/resources/templates/fragments/general.html b/src/main/resources/templates/fragments/general.html
index 34e4b56..80e4a81 100644
--- a/src/main/resources/templates/fragments/general.html
+++ b/src/main/resources/templates/fragments/general.html
@@ -7,7 +7,6 @@
     <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
     <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js"></script>
-    <!--<script src="https://kit.fontawesome.com/22c0caaa8a.js" crossorigin="anonymous"></script>-->
 
     <script type="text/javascript" th:src="@{/js/script.js}"></script>
 
diff --git a/src/main/resources/templates/fragments/groups.html b/src/main/resources/templates/fragments/groups.html
index 4d5f38c..7030f88 100644
--- a/src/main/resources/templates/fragments/groups.html
+++ b/src/main/resources/templates/fragments/groups.html
@@ -7,17 +7,17 @@
 
 <!--Grouptype Badges-->
 <th:block th:fragment="badges">
-    <span class="badge badge-pill private"
+    <span class="badge badge-pill private align-self-start"
           title="Kann nicht über die Suche gefunden werden, beitritt ist per Einladungslink möglich."
           th:if='${group.isPrivate()}'>Privat</span>
-    <span class="badge badge-pill public"
+    <span class="badge badge-pill public align-self-start"
           title="Kann über die Suche gefunden werden, jeder kann beitreten."
           th:if="${group.isPublic()}">Öffentlich</span>
-    <span class="badge badge-pill lecture"
+    <span class="badge badge-pill lecture align-self-start"
           title="Offizielle Veranstaltung"
           th:if='${group.isLecture()}'>Veranstaltung</span>
 
-    <span class="badge badge-pill parent"
+    <span class="badge badge-pill parent align-self-start"
           th:if="${parent?.exists()}"
           th:title="${'Die Gruppe gehört zur Veranstaltung ' + parent.getTitle() + '.'}"
           th:text="${parent.getTitle()}">Parent</span>
@@ -36,7 +36,7 @@
 
 <th:block th:fragment="groupcontent">
     <!--Badges-->
-    <div class="content-heading">
+    <div class="content-heading overflow-hidden">
         <span th:replace="~{fragments/groups :: badges}"></span>
     </div>
 
@@ -48,6 +48,19 @@
     <!--<div class="body-text-in" th:if="${group.getMembers().contains(user.getId())}"></div>-->
 </th:block>
 
+<th:block th:fragment="groupcontentlink">
+    <div class="content-heading row overflow-hidden">
+        <a class="link col" th:href="@{/gruppen2/details/{id}(id=${group.getId()})}"
+           th:text="${group.getTitle()}"></a>
+
+        <span th:replace="~{fragments/groups :: badges}"></span>
+    </div>
+
+    <div class="content-text-in overflow-hidden" style="text-overflow: ellipsis;">
+        <span th:text="${group.getDescription()}"></span>
+    </div>
+</th:block>
+
 <!--Buttonbar zum Gruppe beitreten-->
 <th:block th:fragment="joingroup">
     <div class="content-heading">
@@ -59,15 +72,13 @@
         </span>
     </div>
 
-    <div class="row">
+    <div class="d-flex flex-row flex-wrap">
         <form method="post" th:action="@{/gruppen2/details/{id}/join(id = ${group.getId()})}"
               th:unless="${group.isFull()}">
             <button class="btn btn-success" type="submit">Gruppe beitreten.</button>
         </form>
 
-        <div class="col" th:unless="${group.isFull()}"></div>
-
-        <a class="btn btn-primary" href="/gruppen2"
+        <a class="btn btn-primary ml-auto" href="/gruppen2"
            type="submit">Startseite.</a>
     </div>
 </th:block>
diff --git a/src/main/resources/templates/index.html b/src/main/resources/templates/index.html
index 5a3ef98..8f918c4 100644
--- a/src/main/resources/templates/index.html
+++ b/src/main/resources/templates/index.html
@@ -9,23 +9,26 @@
 <body>
 
 <main th:fragment="bodycontent">
-    <div class="container-fluid">
+    <h1>Meine Gruppen</h1>
 
-        <h1 class="def-cursor">Meine Gruppen</h1>
+    <!--Gruppenliste belegte Gruppen-->
+    <div class="mx-n2 mx-sm-0" th:unless="${lectures.isEmpty()}">
+        <h3>Veranstaltungen</h3>
 
-        <!--Gruppenliste belegte Gruppen-->
-        <div class="content" th:each="group: ${groups}">
-            <div class="content-heading row">
-                <a class="link col" th:href="@{/gruppen2/details/{id}(id=${group.getId()})}"
-                   th:text="${group.getTitle()}"></a>
+        <div class="content px-1 px-sm-3" th:each="group: ${lectures}"
+             th:insert="fragments/groups :: groupcontentlink"></div>
+    </div>
 
-                <span th:replace="~{fragments/groups :: badges}"></span>
-            </div>
-            <div class="content-text-in">
-                <span th:text="${group.getDescription()}"></span>
-            </div>
-        </div>
+    <div class="mx-n2 mx-sm-0" th:unless="${publics.isEmpty()}">
+        <h3>Öffentliche Gruppen</h3>
+        <div class="content px-1 px-sm-3" th:each="group: ${publics}"
+             th:insert="fragments/groups :: groupcontentlink"></div>
+    </div>
 
+    <div class="mx-n2 mx-sm-0" th:unless="${privates.isEmpty()}">
+        <h3>Private Gruppen</h3>
+        <div class="content px-1 px-sm-3" th:each="group: ${privates}"
+             th:insert="fragments/groups :: groupcontentlink"></div>
     </div>
 </main>
 
diff --git a/src/main/resources/templates/link.html b/src/main/resources/templates/link.html
index 5a5741a..c4f8f81 100644
--- a/src/main/resources/templates/link.html
+++ b/src/main/resources/templates/link.html
@@ -10,7 +10,7 @@
 
 <main th:fragment="bodycontent">
     <div class="container-fluid">
-        <h1 class="def-cursor" th:text="${group.getTitle()}"></h1>
+        <h1 th:text="${group.getTitle()}"></h1>
 
         <div class="content" th:insert="~{fragments/groups :: groupcontent}"></div>
 
diff --git a/src/main/resources/templates/log.html b/src/main/resources/templates/log.html
new file mode 100644
index 0000000..f60bd36
--- /dev/null
+++ b/src/main/resources/templates/log.html
@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html lang="de" xmlns:th="http://www.thymeleaf.org" th:replace="~{mopslayout :: html(
+    name='Gruppenfindung',
+    title='Event-Log',
+    headcontent=~{fragments/general :: headcontent('none')},
+    navigation=~{fragments/general :: nav('none')},
+    bodycontent=~{:: bodycontent})}">
+
+<body>
+
+<main th:fragment="bodycontent">
+    <h1>Event-Log</h1>
+
+    <div class="content py-2 px-1 px-sm-3 mx-n2 mx-sm-0" th:each="event : ${events}">
+        <div class="content-heading d-flex flex-row flex-wrap">
+            <span th:text="${event.type()}"></span>
+
+            <span class="ml-auto">Datum: </span>
+            <span th:text="${event.getDate()}"></span>
+        </div>
+
+        <div class="content-text-in px-1 px-sm-3">
+            <span th:text="${'User:' + event.getExec()}"></span>
+
+            <span th:text="${'>>>' + event.format()}"></span>
+        </div>
+    </div>
+</main>
+
+</body>
+</html>
diff --git a/src/main/resources/templates/preview.html b/src/main/resources/templates/preview.html
index 94b6ea0..2b78821 100644
--- a/src/main/resources/templates/preview.html
+++ b/src/main/resources/templates/preview.html
@@ -10,17 +10,15 @@
 
 <main th:fragment="bodycontent">
     <div class="container-fluid">
-        <h1 class="def-cursor" th:text="${group.getTitle()}"></h1>
+        <h1 th:text="${group.getTitle()}"></h1>
 
         <div class="content" th:insert="~{fragments/groups :: groupcontent}"></div>
 
         <div class="content" th:unless="${group.isPrivate()}"
              th:insert="~{fragments/groups :: joingroup}"></div>
 
-        <div class="content row" th:if="${group.isPrivate()}">
-            <span class="col"></span>
-
-            <a class="btn btn-primary" href="/gruppen2">Startseite.</a>
+        <div class="content d-flex flex-row flex-wrap" th:if="${group.isPrivate()}">
+            <a class="btn btn-primary ml-auto" href="/gruppen2">Startseite.</a>
         </div>
     </div>
 </main>
diff --git a/src/main/resources/templates/search.html b/src/main/resources/templates/search.html
index 132d82d..4ed2c60 100644
--- a/src/main/resources/templates/search.html
+++ b/src/main/resources/templates/search.html
@@ -8,38 +8,44 @@
 
 <body>
 
+<!--/*@thymesVar id="LECTURE" type="mops.gruppen2.domain.model.group.Type"*/-->
+<!--/*@thymesVar id="PUBLIC" type="mops.gruppen2.domain.model.group.Type"*/-->
+
 <main th:fragment="bodycontent">
-    <div class="container-fluid">
+    <h1>Suchen</h1>
 
-        <h1>Suchen</h1>
-
-        <!--Suchfilter-->
-        <div class="content top">
-            <form method="post" th:action="@{/gruppen2/search}">
-                <div class="input-group mb-3">
-                    <div class="input-group-prepend">
-                        <span class="input-group-text text-monospace">Suchbegriff:</span>
+    <!--Suchfilter-->
+    <div class="content py-2 px-1 px-sm-3 mx-n2 mx-sm-0">
+        <form method="post" th:action="@{/gruppen2/search/string}">
+            <div class="d-flex flex-row flex-wrap mr-n2 mt-n2">
+                <div class="input-group mr-2 mt-2 flex-grow-1" style="flex-basis: 75%;">
+                    <div class="input-group-prepend" style="max-width: 50%;">
+                            <span class="input-group-text text-monospace overflow-hidden"
+                                  style="text-overflow: ellipsis">Suchbegriff:</span>
                     </div>
-                    <input class="form-control" name="string" type="text">
+                    <input class="form-control" required minlength="1" name="string" type="text">
                 </div>
-                <button class="btn btn-primary" type="submit">Suchen</button>
-            </form>
-        </div>
 
-        <!--Ergebnisliste-->
-        <div class="content" th:each="group: ${groups}">
-            <div class="content-heading row">
-                <span th:replace="~{fragments/groups :: badges}"></span>
-
-                <a class="link col" th:href="@{/gruppen2/details/{id}(id=${group.getId()})}"
-                   th:text="${group.getTitle()}"></a>
+                <button class="btn btn-primary btn-block mr-2 mt-2 flex-grow-1" type="submit">
+                    Suchen
+                </button>
             </div>
-            <div class="content-text-in">
-                <span th:text="${group.getDescription()}"></span>
-            </div>
-        </div>
+        </form>
 
+        <div class="d-flex flex-row flex-wrap mt-1 mr-n2">
+            <a class="btn btn-info mt-2 mr-2 flex-grow-1"
+               th:href="@{/gruppen2/search/all}">Alle Anzeigen</a>
+
+            <a class="btn btn-info mt-2 mr-2 flex-grow-1 ml-auto"
+               th:href="@{/gruppen2/search/type/{type}(type=${LECTURE})}">Vorlesungen</a>
+            <a class="btn btn-info mt-2 mr-2 flex-grow-1"
+               th:href="@{/gruppen2/search/type/{type}(type=${PUBLIC})}">Öffentliche Gruppen</a>
+        </div>
     </div>
+
+    <!--Ergebnisliste-->
+    <div class="content py-2 px-1 px-sm-3 mx-n2 mx-sm-0" th:each="group: ${groups}"
+         th:insert="fragments/groups :: groupcontentlink"></div>
 </main>
 
 </body>
diff --git a/src/test/java/mops/gruppen2/GroupBuilder.java b/src/test/java/mops/gruppen2/GroupBuilder.java
new file mode 100644
index 0000000..154c27c
--- /dev/null
+++ b/src/test/java/mops/gruppen2/GroupBuilder.java
@@ -0,0 +1,154 @@
+package mops.gruppen2;
+
+import mops.gruppen2.domain.event.AddMemberEvent;
+import mops.gruppen2.domain.event.CreateGroupEvent;
+import mops.gruppen2.domain.event.DestroyGroupEvent;
+import mops.gruppen2.domain.event.Event;
+import mops.gruppen2.domain.event.KickMemberEvent;
+import mops.gruppen2.domain.event.SetDescriptionEvent;
+import mops.gruppen2.domain.event.SetInviteLinkEvent;
+import mops.gruppen2.domain.event.SetLimitEvent;
+import mops.gruppen2.domain.event.SetTitleEvent;
+import mops.gruppen2.domain.event.SetTypeEvent;
+import mops.gruppen2.domain.event.UpdateRoleEvent;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.Role;
+import mops.gruppen2.domain.model.group.Type;
+import mops.gruppen2.domain.model.group.User;
+import mops.gruppen2.domain.model.group.wrapper.Description;
+import mops.gruppen2.domain.model.group.wrapper.Limit;
+import mops.gruppen2.domain.model.group.wrapper.Link;
+import mops.gruppen2.domain.model.group.wrapper.Title;
+import mops.gruppen2.infrastructure.GroupCache;
+
+import java.time.LocalDateTime;
+import java.util.UUID;
+
+import static mops.gruppen2.TestHelper.uuid;
+
+public final class GroupBuilder {
+
+    private final UUID groupid;
+    private int version;
+    private final GroupCache groupCache;
+    private final Group group = Group.EMPTY();
+
+    private GroupBuilder(GroupCache cache, UUID id) {
+        groupCache = cache;
+        groupid = id;
+    }
+
+    /**
+     * Erzeugt neuen GruppenBuilder mit Cache und ID
+     */
+    public static GroupBuilder get(GroupCache cache, int id) {
+        return new GroupBuilder(cache, uuid(id));
+    }
+
+    /**
+     * Initialisiert Gruppe mit Id, Creator und Zeit
+     */
+    public GroupBuilder group() {
+        return apply(new CreateGroupEvent(groupid, "TEST", LocalDateTime.now()));
+    }
+
+    /**
+     * Initialisiert TestAdmin
+     */
+    public GroupBuilder testadmin() {
+        apply(new AddMemberEvent(groupid, "TEST", "TEST", new User("TEST")));
+        return apply(new UpdateRoleEvent(groupid, "TEST", "TEST", Role.ADMIN));
+    }
+
+    /**
+     * Fügt Nutzer hinzu
+     */
+    public GroupBuilder add(String userid) {
+        return apply(new AddMemberEvent(groupid, "TEST", userid, new User(userid)));
+    }
+
+    /**
+     * Entfernt Nutzer
+     */
+    public GroupBuilder kick(String userid) {
+        return apply(new KickMemberEvent(groupid, "TEST", userid));
+    }
+
+    public GroupBuilder limit(int i) {
+        return apply(new SetLimitEvent(groupid, "TEST", new Limit(i)));
+    }
+
+    /**
+     * Macht Nutzer zu Admin
+     */
+    public GroupBuilder admin(String userid) {
+        return apply(new UpdateRoleEvent(groupid, "TEST", userid, Role.ADMIN));
+    }
+
+    /**
+     * Macht Nutzer zu regulärem
+     */
+    public GroupBuilder regular(String userid) {
+        return apply(new UpdateRoleEvent(groupid, "TEST", userid, Role.REGULAR));
+    }
+
+    /**
+     * Macht Gruppe öffentlich
+     */
+    public GroupBuilder publik() {
+        return apply(new SetTypeEvent(groupid, "TEST", Type.PUBLIC));
+    }
+
+    /**
+     * Macht Gruppe privat
+     */
+    public GroupBuilder privat() {
+        return apply(new SetTypeEvent(groupid, "TEST", Type.PRIVATE));
+    }
+
+    /**
+     * Macht Gruppe zu Veranstaltung
+     */
+    public GroupBuilder lecture() {
+        return apply(new SetTypeEvent(groupid, "TEST", Type.LECTURE));
+    }
+
+    /**
+     * Setzt Beschreibung
+     */
+    public GroupBuilder desc(String descr) {
+        return apply(new SetDescriptionEvent(groupid, "TEST", new Description(descr)));
+    }
+
+    /**
+     * Setzt Titel
+     */
+    public GroupBuilder title(String titl) {
+        return apply(new SetTitleEvent(groupid, "TEST", new Title(titl)));
+    }
+
+    /**
+     * Setzt Link
+     */
+    public GroupBuilder link(int lnk) {
+        return apply(new SetInviteLinkEvent(groupid, "TEST", new Link(uuid(lnk).toString())));
+    }
+
+    /**
+     * Löscht Gruppe
+     */
+    public GroupBuilder destroy() {
+        return apply(new DestroyGroupEvent(groupid, "TEST"));
+    }
+
+    public Group build() {
+        return group;
+    }
+
+    private GroupBuilder apply(Event event) {
+        version++;
+        event.init(version);
+        event.apply(group, groupCache);
+        return this;
+    }
+}
diff --git a/src/test/java/mops/gruppen2/TestBuilder.java b/src/test/java/mops/gruppen2/TestBuilder.java
deleted file mode 100644
index d1c666a..0000000
--- a/src/test/java/mops/gruppen2/TestBuilder.java
+++ /dev/null
@@ -1,297 +0,0 @@
-package mops.gruppen2;
-
-public class TestBuilder {
-
-    /*private static final Faker faker = new Faker();
-
-    public static Account account(String name) {
-        return new Account(name,
-                           "",
-                           "",
-                           "",
-                           "",
-                           null);
-    }
-
-    public static Group apply(Group group, Event... events) {
-        for (Event event : events) {
-            event.apply(group);
-        }
-
-        return group;
-    }
-
-    public static Group apply(Event... events) {
-        return apply(new Group(), events);
-    }
-
-    *//**
-     * Baut eine UUID.
-     *
-     * @param id Integer id
-     *
-     * @return UUID
-     *//*
-    public static UUID uuidMock(int id) {
-        String idString = String.valueOf(Math.abs(id + 1));
-        return UUID.fromString("00000000-0000-0000-0000-"
-                               + "0".repeat(11 - idString.length())
-                               + idString);
-    }
-
-    *//**
-     * Generiert ein EventLog mit mehreren Gruppen und Usern.
-     *
-     * @param count       Gruppenanzahl
-     * @param membercount Mitgliederanzahl pro Gruppe
-     *
-     * @return Eventliste
-     *//*
-    public static List<Event> completePublicGroups(int count, int membercount) {
-        return IntStream.range(0, count)
-                        .parallel()
-                        .mapToObj(i -> completePublicGroup(membercount))
-                        .flatMap(Collection::stream)
-                        .collect(Collectors.toList());
-    }
-
-    public static List<Event> completePrivateGroups(int count, int membercount) {
-        return IntStream.range(0, count)
-                        .parallel()
-                        .mapToObj(i -> completePrivateGroup(membercount))
-                        .flatMap(Collection::stream)
-                        .collect(Collectors.toList());
-    }
-
-    public static List<Event> completePublicGroup(int membercount) {
-        List<Event> eventList = new ArrayList<>();
-        UUID groupId = UUID.randomUUID();
-
-        eventList.add(createPublicGroupEvent(groupId));
-        eventList.add(updateGroupTitleEvent(groupId));
-        eventList.add(updateGroupDescriptionEvent(groupId));
-        eventList.add(new SetLimitEvent(groupId, "fgsadggas", new Limit(Long.MAX_VALUE)));
-        eventList.addAll(addUserEvents(membercount, groupId));
-
-        return eventList;
-    }
-
-    public static List<Event> completePrivateGroup(int membercount) {
-        List<Event> eventList = new ArrayList<>();
-        UUID groupId = UUID.randomUUID();
-
-        eventList.add(createPrivateGroupEvent(groupId));
-        eventList.add(updateGroupTitleEvent(groupId));
-        eventList.add(updateGroupDescriptionEvent(groupId));
-        eventList.add(new SetLimitEvent(groupId, "fgsadggas", new Limit(Long.MAX_VALUE)));
-        eventList.addAll(addUserEvents(membercount, groupId));
-
-        return eventList;
-    }
-
-    public static List<Event> completePublicGroup() {
-        return completePublicGroup(100);
-    }
-
-    public static List<Event> completePrivateGroup() {
-        return completePrivateGroup(100);
-    }
-
-    *//**
-     * Generiert mehrere CreateGroupEvents, 1 <= groupId <= count.
-     *
-     * @param count Anzahl der verschiedenen Gruppen
-     *
-     * @return Eventliste
-     *//*
-    public static List<Event> createPublicGroupEvents(int count) {
-        return IntStream.range(0, count)
-                        .parallel()
-                        .mapToObj(i -> createPublicGroupEvent())
-                        .collect(Collectors.toList());
-    }
-
-    public static List<Event> createPrivateGroupEvents(int count) {
-        return IntStream.range(0, count)
-                        .parallel()
-                        .mapToObj(i -> createPublicGroupEvent())
-                        .collect(Collectors.toList());
-    }
-
-    public static List<Event> createMixedGroupEvents(int count) {
-        return IntStream.range(0, count)
-                        .parallel()
-                        .mapToObj(i -> faker.random().nextInt(0, 1) > 0.5
-                                ? createPublicGroupEvent()
-                                : createPrivateGroupEvent())
-                        .collect(Collectors.toList());
-    }
-
-    public static List<Event> createPrivateGroupEvents(UUID groupId) {
-        return (new ArrayList<>()).addAll(createGroupEvent(groupId)),
-        new SetTypeEvent(groupId);
-    }
-
-    public static Event createPrivateGroupEvent() {
-        return createPrivateGroupEvent(UUID.randomUUID());
-    }
-
-    public static Event createPublicGroupEvent(UUID groupId) {
-        return createGroupEvent(groupId, Type.PUBLIC);
-    }
-
-    public static Event createPublicGroupEvent() {
-        return createPublicGroupEvent(UUID.randomUUID());
-    }
-
-    public static Event createGroupEvent(UUID groupId) {
-        return new CreateGroupEvent(groupId,
-                                    faker.random().hex(),
-                                    LocalDateTime.now());
-    }
-
-    public static Event createLectureEvent() {
-        return createLectureEvent(UUID.randomUUID());
-    }
-
-    public static Event createLectureEvent(UUID groupId) {
-        return new CreateGroupEvent(
-                groupId,
-                faker.random().hex(),
-                null,
-                Type.LECTURE
-        );
-    }
-
-    *//**
-     * Generiert mehrere AddUserEvents für eine Gruppe, 1 <= user_id <= count.
-     *
-     * @param count   Anzahl der Mitglieder
-     * @param groupId Gruppe, zu welcher geaddet wird
-     *
-     * @return Eventliste
-     *//*
-    public static List<Event> addUserEvents(int count, UUID groupId) {
-        return IntStream.range(0, count)
-                        .parallel()
-                        .mapToObj(i -> addUserEvent(groupId, String.valueOf(i)))
-                        .collect(Collectors.toList());
-    }
-
-    public static Event addUserEvent(UUID groupId, String userId) {
-        String firstname = firstname();
-        String lastname = lastname();
-
-        return new AddMemberEvent(
-                groupId,
-                userId,
-                firstname,
-                lastname,
-                firstname + "." + lastname + "@mail.de"
-        );
-    }
-
-    public static Event addUserEvent(UUID groupId) {
-        return addUserEvent(groupId, faker.random().hex());
-    }
-
-    // Am besten einfach nicht benutzen
-    public static List<Event> deleteUserEvents(int count, List<Event> eventList) {
-        List<Event> removeEvents = new ArrayList<>();
-        List<Event> shuffle = eventList.parallelStream()
-                                       .filter(event -> event instanceof AddMemberEvent)
-                                       .collect(Collectors.toList());
-
-        Collections.shuffle(shuffle);
-
-        for (Event event : shuffle) {
-            removeEvents.add(new KickMemberEvent(event.getGroupid(), event.getTarget()));
-
-            if (removeEvents.size() >= count) {
-                break;
-            }
-        }
-
-        return removeEvents;
-    }
-
-    *//**
-     * Erzeugt mehrere DeleteUserEvents, sodass eine Gruppe komplett geleert wird.
-     *
-     * @param group Gruppe welche geleert wird
-     *
-     * @return Eventliste
-     *//*
-    public static List<Event> deleteUserEvents(Group group) {
-        return group.getMemberships().parallelStream()
-                    .map(user -> deleteUserEvent(group.getGroupid(), user.getUserId()))
-                    .collect(Collectors.toList());
-    }
-
-    public static Event deleteUserEvent(UUID groupId, String userId) {
-        return new KickMemberEvent(
-                groupId,
-                userId
-        );
-    }
-
-    public static Event updateGroupDescriptionEvent(UUID groupId) {
-        return updateGroupDescriptionEvent(groupId, quote());
-    }
-
-    public static Event updateGroupDescriptionEvent(UUID groupId, String description) {
-        return new SetDescriptionEvent(
-                groupId,
-                faker.random().hex(),
-                description
-        );
-    }
-
-    public static Event updateGroupTitleEvent(UUID groupId) {
-        return updateGroupTitleEvent(groupId, champion());
-    }
-
-    public static Event updateGroupTitleEvent(UUID groupId, String title) {
-        return new SetTitleEvent(
-                groupId,
-                faker.random().hex(),
-                title
-        );
-    }
-
-    public static Event updateUserLimitMaxEvent(UUID groupId) {
-        return new SetLimitEvent(groupId, firstname(), Long.MAX_VALUE);
-    }
-
-    public static Event updateRoleEvent(UUID groupId, String userId, Role role) {
-        return new UpdateRoleEvent(
-                groupId,
-                userId,
-                role
-        );
-    }
-
-    public static Event deleteGroupEvent(UUID groupId) {
-        return new DestroyGroupEvent(groupId, faker.random().hex());
-    }
-
-    private static String firstname() {
-        return clean(faker.name().firstName());
-    }
-
-    private static String lastname() {
-        return clean(faker.name().lastName());
-    }
-
-    private static String champion() {
-        return clean(faker.leagueOfLegends().champion());
-    }
-
-    private static String quote() {
-        return clean(faker.leagueOfLegends().quote());
-    }
-
-    private static String clean(String string) {
-        return string.replaceAll("['\";,]", "");
-    }*/
-}
diff --git a/src/test/java/mops/gruppen2/TestHelper.java b/src/test/java/mops/gruppen2/TestHelper.java
new file mode 100644
index 0000000..ad9968c
--- /dev/null
+++ b/src/test/java/mops/gruppen2/TestHelper.java
@@ -0,0 +1,24 @@
+package mops.gruppen2;
+
+import mops.gruppen2.domain.event.Event;
+
+import java.util.List;
+import java.util.UUID;
+
+public final class TestHelper {
+
+    public static UUID uuid(int id) {
+        String num = String.valueOf(id);
+        String string = "00000000-0000-0000-0000-";
+        string += "0".repeat(12 - num.length());
+        string += num;
+
+        return UUID.fromString(string);
+    }
+
+    public static void initEvents(List<Event> events) {
+        for (int i = 1; i <= events.size(); i++) {
+            events.get(i - 1).init(i);
+        }
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/event/AddMemberEventTest.java b/src/test/java/mops/gruppen2/domain/event/AddMemberEventTest.java
new file mode 100644
index 0000000..e48fbe3
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/event/AddMemberEventTest.java
@@ -0,0 +1,76 @@
+package mops.gruppen2.domain.event;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.TestHelper;
+import mops.gruppen2.domain.exception.GroupFullException;
+import mops.gruppen2.domain.exception.IdMismatchException;
+import mops.gruppen2.domain.exception.UserExistsException;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.User;
+import mops.gruppen2.domain.service.EventStoreService;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.Mockito.mock;
+
+class AddMemberEventTest {
+
+    GroupCache cache;
+
+    @BeforeEach
+    void setUp() {
+        cache = new GroupCache(mock(EventStoreService.class));
+    }
+
+    @Test
+    void userMismatch() {
+        assertThatThrownBy(() -> new AddMemberEvent(TestHelper.uuid(1), "TEST", "TEST", new User("PETER")))
+                .isInstanceOf(IdMismatchException.class);
+    }
+
+    @Test
+    void apply() {
+        Group group = GroupBuilder.get(cache, 1).group().build();
+        Event add = new AddMemberEvent(TestHelper.uuid(1), "TEST", "TEST", new User("TEST"));
+        add.init(2);
+
+        add.apply(group);
+
+        assertThat(group.getMembers()).containsExactly(new User("TEST"));
+    }
+
+    @Test
+    void apply_cache() {
+        Group group = GroupBuilder.get(cache, 1).group().build();
+        Event add = new AddMemberEvent(TestHelper.uuid(1), "TEST", "TEST", new User("TEST"));
+        add.init(2);
+
+        add.apply(group, cache);
+
+        assertThat(group.getMembers()).containsExactly(new User("TEST"));
+        assertThat(cache.userGroups("TEST")).containsExactly(group);
+    }
+
+    @Test
+    void apply_userExists() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().limit(2).build();
+        Event add = new AddMemberEvent(TestHelper.uuid(1), "TEST", "TEST", new User("TEST"));
+        add.init(5);
+
+        assertThatThrownBy(() -> add.apply(group, cache))
+                .isInstanceOf(UserExistsException.class);
+    }
+
+    @Test
+    void apply_groupFull() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().build();
+        Event add = new AddMemberEvent(TestHelper.uuid(1), "TEST", "PETER", new User("PETER"));
+        add.init(4);
+
+        assertThatThrownBy(() -> add.apply(group, cache))
+                .isInstanceOf(GroupFullException.class);
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/event/CreateGroupEventTest.java b/src/test/java/mops/gruppen2/domain/event/CreateGroupEventTest.java
new file mode 100644
index 0000000..ae720de
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/event/CreateGroupEventTest.java
@@ -0,0 +1,45 @@
+package mops.gruppen2.domain.event;
+
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.service.EventStoreService;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDateTime;
+
+import static mops.gruppen2.TestHelper.uuid;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+class CreateGroupEventTest {
+
+    GroupCache cache;
+
+    @BeforeEach
+    void setUp() {
+        cache = new GroupCache(mock(EventStoreService.class));
+    }
+
+    @Test
+    void apply() {
+        Group group = Group.EMPTY();
+        Event add = new CreateGroupEvent(uuid(1), "TEST", LocalDateTime.now());
+        add.init(1);
+
+        assertThat(group.exists()).isFalse();
+        add.apply(group);
+        assertThat(group.exists()).isTrue();
+    }
+
+    @Test
+    void apply_cache() {
+        Group group = Group.EMPTY();
+        Event add = new CreateGroupEvent(uuid(1), "TEST", LocalDateTime.now());
+        add.init(1);
+
+        add.apply(group, cache);
+        assertThat(group.exists()).isTrue();
+        assertThat(cache.groups()).hasSize(1);
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/event/DestroyGroupEventTest.java b/src/test/java/mops/gruppen2/domain/event/DestroyGroupEventTest.java
new file mode 100644
index 0000000..fa2634b
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/event/DestroyGroupEventTest.java
@@ -0,0 +1,110 @@
+package mops.gruppen2.domain.event;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.domain.exception.NoAccessException;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.service.EventStoreService;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static mops.gruppen2.TestHelper.uuid;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.Mockito.mock;
+
+class DestroyGroupEventTest {
+
+    GroupCache cache;
+
+    @BeforeEach
+    void setUp() {
+        cache = new GroupCache(mock(EventStoreService.class));
+    }
+
+    @Test
+    void apply() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().build();
+        Event destroy = new DestroyGroupEvent(uuid(1), "TEST");
+        destroy.init(4);
+
+        assertThat(group.exists()).isTrue();
+        destroy.apply(group);
+        assertThat(group.exists()).isFalse();
+    }
+
+    @Test
+    void apply_noadmin() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().limit(3).add("PETER").build();
+        Event destroy = new DestroyGroupEvent(uuid(1), "PETER");
+        destroy.init(6);
+
+        assertThatThrownBy(() -> destroy.apply(group))
+                .isInstanceOf(NoAccessException.class);
+    }
+
+    @Test
+    void apply_noadmin_empty() {
+        Group group = GroupBuilder.get(cache, 1).group().build();
+        Event destroy = new DestroyGroupEvent(uuid(1), "PETER");
+        destroy.init(2);
+
+        destroy.apply(group);
+    }
+
+    @Test
+    void apply_cache_private() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().privat().build();
+        Event destroy = new DestroyGroupEvent(uuid(1), "TEST");
+        destroy.init(5);
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userGroups("TEST")).hasSize(1);
+        assertThat(cache.privates()).hasSize(1);
+        destroy.apply(group, cache);
+        assertThat(cache.groups()).isEmpty();
+        assertThat(cache.userGroups("TEST")).isEmpty();
+        assertThat(cache.privates()).isEmpty();
+    }
+
+    @Test
+    void apply_cache_public() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().publik().build();
+        Event destroy = new DestroyGroupEvent(uuid(1), "TEST");
+        destroy.init(5);
+
+        assertThat(cache.publics()).hasSize(1);
+        destroy.apply(group, cache);
+        assertThat(cache.publics()).isEmpty();
+    }
+
+    @Test
+    void apply_cache_lecture() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().lecture().build();
+        Event destroy = new DestroyGroupEvent(uuid(1), "TEST");
+        destroy.init(5);
+
+        assertThat(cache.lectures()).hasSize(1);
+        destroy.apply(group, cache);
+        assertThat(cache.lectures()).isEmpty();
+    }
+
+    @Test
+    void apply_cache_multipleUsers() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().privat().limit(5).add("A").add("B").add("C").add("D").build();
+        Event destroy = new DestroyGroupEvent(uuid(1), "TEST");
+        destroy.init(10);
+
+        assertThat(cache.userGroups("TEST")).hasSize(1);
+        assertThat(cache.userGroups("A")).hasSize(1);
+        assertThat(cache.userGroups("B")).hasSize(1);
+        assertThat(cache.userGroups("C")).hasSize(1);
+        assertThat(cache.userGroups("D")).hasSize(1);
+        destroy.apply(group, cache);
+        assertThat(cache.userGroups("TEST")).hasSize(0);
+        assertThat(cache.userGroups("A")).hasSize(0);
+        assertThat(cache.userGroups("B")).hasSize(0);
+        assertThat(cache.userGroups("C")).hasSize(0);
+        assertThat(cache.userGroups("D")).hasSize(0);
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/event/EventTest.java b/src/test/java/mops/gruppen2/domain/event/EventTest.java
new file mode 100644
index 0000000..6998d42
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/event/EventTest.java
@@ -0,0 +1,76 @@
+package mops.gruppen2.domain.event;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.domain.exception.BadArgumentException;
+import mops.gruppen2.domain.exception.IdMismatchException;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.User;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import static mops.gruppen2.TestHelper.uuid;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+public class EventTest {
+
+    @Test
+    void apply_smallVersion() {
+        Group group = GroupBuilder.get(Mockito.mock(GroupCache.class), 1).group().build();
+        Event add = new AddMemberEvent(uuid(1), "TEST", "TEST", new User("TEST"));
+        add.init(1);
+
+        assertThatThrownBy(() -> add.apply(group))
+                .isInstanceOf(IdMismatchException.class);
+    }
+
+    @Test
+    void apply_bigVersion() {
+        Group group = GroupBuilder.get(Mockito.mock(GroupCache.class), 1).group().build();
+        Event add = new AddMemberEvent(uuid(1), "TEST", "TEST", new User("TEST"));
+        add.init(3);
+
+        assertThatThrownBy(() -> add.apply(group))
+                .isInstanceOf(IdMismatchException.class);
+    }
+
+    @Test
+    void apply_notInitialized() {
+        Group group = GroupBuilder.get(Mockito.mock(GroupCache.class), 1).group().build();
+        Event add = new AddMemberEvent(uuid(1), "TEST", "TEST", new User("TEST"));
+
+        assertThatThrownBy(() -> add.apply(group))
+                .isInstanceOf(BadArgumentException.class);
+    }
+
+    @Test
+    void apply_wrongGroup() {
+        Group group = GroupBuilder.get(Mockito.mock(GroupCache.class), 1).group().build();
+        Event add = new AddMemberEvent(uuid(2), "TEST", "TEST", new User("TEST"));
+        add.init(2);
+
+        assertThatThrownBy(() -> add.apply(group))
+                .isInstanceOf(IdMismatchException.class);
+    }
+
+    @Test
+    void apply_updateVersion() {
+        Group group = GroupBuilder.get(Mockito.mock(GroupCache.class), 1).group().build();
+        Event add = new AddMemberEvent(uuid(1), "TEST", "TEST", new User("TEST"));
+        add.init(2);
+
+        assertThat(group.getVersion()).isEqualTo(1);
+        add.apply(group);
+        assertThat(group.getVersion()).isEqualTo(2);
+    }
+
+    @Test
+    void init_alreadyInitialized() {
+        Event add = new AddMemberEvent(uuid(1), "TEST", "TEST", new User("TEST"));
+        add.init(2);
+
+        assertThatThrownBy(() -> add.init(3))
+                .isInstanceOf(BadArgumentException.class);
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/event/KickMemberEventTest.java b/src/test/java/mops/gruppen2/domain/event/KickMemberEventTest.java
new file mode 100644
index 0000000..51765f7
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/event/KickMemberEventTest.java
@@ -0,0 +1,44 @@
+package mops.gruppen2.domain.event;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.service.EventStoreService;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static mops.gruppen2.TestHelper.uuid;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+class KickMemberEventTest {
+
+    GroupCache cache;
+
+    @BeforeEach
+    void setUp() {
+        cache = new GroupCache(mock(EventStoreService.class));
+    }
+
+    @Test
+    void apply() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().build();
+        Event kick = new KickMemberEvent(uuid(1), "TEST", "TEST");
+        kick.init(4);
+
+        assertThat(group.size()).isOne();
+        kick.apply(group);
+        assertThat(group.size()).isZero();
+    }
+
+    @Test
+    void apply_cache() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().build();
+        Event kick = new KickMemberEvent(uuid(1), "TEST", "TEST");
+        kick.init(4);
+
+        assertThat(cache.userGroups("TEST")).hasSize(1);
+        kick.apply(group, cache);
+        assertThat(cache.userGroups("TEST")).hasSize(0);
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/event/SetInviteLinkEventTest.java b/src/test/java/mops/gruppen2/domain/event/SetInviteLinkEventTest.java
new file mode 100644
index 0000000..d009529
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/event/SetInviteLinkEventTest.java
@@ -0,0 +1,44 @@
+package mops.gruppen2.domain.event;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.wrapper.Link;
+import mops.gruppen2.domain.service.EventStoreService;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static mops.gruppen2.TestHelper.uuid;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+class SetInviteLinkEventTest {
+
+    GroupCache cache;
+
+    @BeforeEach
+    void setUp() {
+        cache = new GroupCache(mock(EventStoreService.class));
+    }
+
+    @Test
+    void apply() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().build();
+        Event link = new SetInviteLinkEvent(uuid(1), "TEST", new Link(uuid(2).toString()));
+        link.init(4);
+
+        link.apply(group);
+        assertThat(group.getLink()).isEqualTo(uuid(2).toString());
+    }
+
+    @Test
+    void apply_cache() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().build();
+        Event link = new SetInviteLinkEvent(uuid(1), "TEST", new Link(uuid(2).toString()));
+        link.init(4);
+
+        assertThat(cache.group(group.getLink())).isEqualTo(group);
+        link.apply(group, cache);
+        assertThat(cache.group(uuid(2).toString())).isEqualTo(group);
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/event/SetLimitEventTest.java b/src/test/java/mops/gruppen2/domain/event/SetLimitEventTest.java
new file mode 100644
index 0000000..c23ace3
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/event/SetLimitEventTest.java
@@ -0,0 +1,34 @@
+package mops.gruppen2.domain.event;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.domain.exception.BadArgumentException;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.wrapper.Limit;
+import mops.gruppen2.domain.service.EventStoreService;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static mops.gruppen2.TestHelper.uuid;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.Mockito.mock;
+
+class SetLimitEventTest {
+
+    GroupCache cache;
+
+    @BeforeEach
+    void setUp() {
+        cache = new GroupCache(mock(EventStoreService.class));
+    }
+
+    @Test
+    void apply_tooSmall() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().limit(2).add("PETER").build();
+        Event limit = new SetLimitEvent(uuid(1), "TEST", new Limit(1));
+        limit.init(6);
+
+        assertThatThrownBy(() -> limit.apply(group))
+                .isInstanceOf(BadArgumentException.class);
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/event/SetTypeEventTest.java b/src/test/java/mops/gruppen2/domain/event/SetTypeEventTest.java
new file mode 100644
index 0000000..892325f
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/event/SetTypeEventTest.java
@@ -0,0 +1,36 @@
+package mops.gruppen2.domain.event;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.Type;
+import mops.gruppen2.domain.service.EventStoreService;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static mops.gruppen2.TestHelper.uuid;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+class SetTypeEventTest {
+
+    GroupCache cache;
+
+    @BeforeEach
+    void setUp() {
+        cache = new GroupCache(mock(EventStoreService.class));
+    }
+
+    @Test
+    void apply_cache() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().privat().build();
+        Event type = new SetTypeEvent(uuid(1), "TEST", Type.LECTURE);
+        type.init(5);
+
+        assertThat(cache.privates()).hasSize(1);
+        assertThat(cache.lectures()).isEmpty();
+        type.apply(group, cache);
+        assertThat(cache.lectures()).hasSize(1);
+        assertThat(cache.privates()).isEmpty();
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/service/GroupServiceTest.java b/src/test/java/mops/gruppen2/domain/service/GroupServiceTest.java
new file mode 100644
index 0000000..2effa8e
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/service/GroupServiceTest.java
@@ -0,0 +1,267 @@
+package mops.gruppen2.domain.service;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.domain.exception.BadArgumentException;
+import mops.gruppen2.domain.exception.GroupFullException;
+import mops.gruppen2.domain.exception.LastAdminException;
+import mops.gruppen2.domain.exception.NoAccessException;
+import mops.gruppen2.domain.exception.UserExistsException;
+import mops.gruppen2.domain.exception.UserNotFoundException;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.Type;
+import mops.gruppen2.domain.model.group.User;
+import mops.gruppen2.domain.model.group.wrapper.Description;
+import mops.gruppen2.domain.model.group.wrapper.Limit;
+import mops.gruppen2.domain.model.group.wrapper.Link;
+import mops.gruppen2.domain.model.group.wrapper.Parent;
+import mops.gruppen2.domain.model.group.wrapper.Title;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+
+import static mops.gruppen2.TestHelper.uuid;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.Mockito.mock;
+
+class GroupServiceTest {
+
+    private GroupService groupService;
+
+    @BeforeEach
+    void setUp() {
+        groupService = new GroupService(mock(GroupCache.class), mock(EventStoreService.class));
+    }
+
+    @Test
+    void createGroup() {
+        Group group = groupService.createGroup("TEST");
+
+        assertThat(group.getId()).isNotNull();
+        assertThat(group.creator()).isEqualTo("TEST");
+    }
+
+    @Test
+    void initGroupMembers() {
+        Group group = groupService.createGroup("TEST");
+        groupService.initGroupMembers(group, "TEST", "TEST", new User("TEST"), new Limit(1));
+
+        assertThat(group.getMembers()).containsExactly(new User("TEST"));
+        assertThat(group.getLimit()).isEqualTo(1);
+        assertThat(group.isAdmin("TEST")).isTrue();
+    }
+
+    @Test
+    void initGroupMeta() {
+        Group group = groupService.createGroup("TEST");
+        groupService.initGroupMembers(group, "TEST", "TEST", new User("TEST"), new Limit(1));
+        groupService.initGroupMeta(group, "TEST", Type.PUBLIC, Parent.EMPTY());
+
+        assertThat(group.isPublic()).isTrue();
+        assertThat(group.hasParent()).isFalse();
+    }
+
+    @Test
+    void initGroupText() {
+        Group group = groupService.createGroup("TEST");
+        groupService.initGroupMembers(group, "TEST", "TEST", new User("TEST"), new Limit(1));
+        groupService.initGroupMeta(group, "TEST", Type.PUBLIC, Parent.EMPTY());
+        groupService.initGroupText(group, "TEST", new Title("TITLE"), new Description("DESCR"));
+
+        assertThat(group.getTitle()).isEqualTo("TITLE");
+        assertThat(group.getDescription()).isEqualTo("DESCR");
+    }
+
+    @Test
+    void addUsersToGroup() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        groupService.addUsersToGroup(group, "TEST", Arrays.asList(
+                new User("A"),
+                new User("B"),
+                new User("C"),
+                new User("C")));
+
+        assertThat(group.getLimit()).isEqualTo(4);
+        assertThat(group.size()).isEqualTo(4);
+        assertThat(group.getRegulars()).hasSize(3);
+        assertThat(group.getAdmins()).hasSize(1);
+    }
+
+    @Test
+    void toggleMemberRole_lastAdmin_lastUser() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        groupService.toggleMemberRole(group, "TEST", "TEST");
+    }
+
+    @Test
+    void toggleMemberRole_lastAdmin() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().limit(2).add("PETER").build();
+
+        assertThatThrownBy(() -> groupService.toggleMemberRole(group, "TEST", "TEST"))
+                .isInstanceOf(LastAdminException.class);
+    }
+
+    @Test
+    void toggleMemberRole_noMember() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        assertThatThrownBy(() -> groupService.toggleMemberRole(group, "TEST", "PETER"))
+                .isInstanceOf(UserNotFoundException.class);
+    }
+
+    @Test
+    void addMember_newMember() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().limit(2).build();
+
+        groupService.addMember(group, "Test", "PETER", new User("PETER"));
+
+        assertThat(group.size()).isEqualTo(2);
+        assertThat(group.getAdmins()).hasSize(1);
+        assertThat(group.getRegulars()).hasSize(1);
+    }
+
+    @Test
+    void addMember_newMember_groupFull() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        assertThatThrownBy(() -> groupService.addMember(group, "Test", "PETER", new User("PETER")))
+                .isInstanceOf(GroupFullException.class);
+    }
+
+    @Test
+    void addMember_newMember_userExists() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().limit(3).add("PETER").build();
+
+        assertThatThrownBy(() -> groupService.addMember(group, "Test", "PETER", new User("PETER")))
+                .isInstanceOf(UserExistsException.class);
+    }
+
+    @Test
+    void kickMember_noMember() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        assertThatThrownBy(() -> groupService.kickMember(group, "TEST", "PETER"))
+                .isInstanceOf(UserNotFoundException.class);
+    }
+
+    @Test
+    void kickMember_lastMember() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        groupService.kickMember(group, "TEST", "TEST");
+
+        assertThat(group.exists()).isFalse();
+    }
+
+    @Test
+    void kickMember_lastAdmin() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().limit(2).add("PETER").build();
+
+        assertThatThrownBy(() -> groupService.kickMember(group, "TEST", "TEST"))
+                .isInstanceOf(LastAdminException.class);
+    }
+
+    @Test
+    void deleteGroup_noGroup() {
+        groupService.deleteGroup(Group.EMPTY(), "TEST");
+    }
+
+    @Test
+    void deleteGroup() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().limit(2).add("PETER").build();
+
+        groupService.deleteGroup(group, "TEST");
+
+        assertThat(group.exists()).isFalse();
+    }
+
+    @Test
+    void deleteGroup_noAdmin() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().limit(2).add("PETER").build();
+
+        assertThatThrownBy(() -> groupService.deleteGroup(group, "PETER"))
+                .isInstanceOf(NoAccessException.class);
+        assertThat(group.exists()).isTrue();
+    }
+
+    @Test
+    void setTitle() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        groupService.setTitle(group, "TEST", new Title("TITLE"));
+
+        assertThat(group.getTitle()).isEqualTo("TITLE");
+    }
+
+    @Test
+    void setDescription() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        groupService.setDescription(group, "TEST", new Description("DESCR"));
+
+        assertThat(group.getDescription()).isEqualTo("DESCR");
+    }
+
+    @Test
+    void setLimit_tooLow() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().limit(2).add("PETER").build();
+
+        assertThatThrownBy(() -> groupService.setLimit(group, "TEST", new Limit(1)))
+                .isInstanceOf(BadArgumentException.class);
+
+        assertThat(group.getLimit()).isEqualTo(2);
+    }
+
+    @Test
+    void setLimit() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        groupService.setLimit(group, "TEST", new Limit(8));
+
+        assertThat(group.getLimit()).isEqualTo(8);
+    }
+
+    @Test
+    void setParent_sameGroup() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        assertThatThrownBy(() -> groupService.setParent(group, "TEST", new Parent(uuid(1).toString())))
+                .isInstanceOf(BadArgumentException.class);
+
+        assertThat(group.getParent()).isEqualTo(uuid(0));
+        assertThat(group.hasParent()).isFalse();
+    }
+
+    @Test
+    void setParent() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        groupService.setParent(group, "TEST", new Parent(uuid(2).toString()));
+
+        assertThat(group.getParent()).isEqualTo(uuid(2));
+        assertThat(group.hasParent()).isTrue();
+    }
+
+    @Test
+    void setLink_sameAsGroupId() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        assertThatThrownBy(() -> groupService.setLink(group, "TEST", new Link(uuid(1).toString())))
+                .isInstanceOf(BadArgumentException.class);
+
+        assertThat(group.getLink()).isNotEqualTo(uuid(1).toString());
+    }
+
+    @Test
+    void setLink() {
+        Group group = GroupBuilder.get(mock(GroupCache.class), 1).group().testadmin().build();
+
+        groupService.setLink(group, "TEST", new Link(uuid(2).toString()));
+
+        assertThat(group.getLink()).isEqualTo(uuid(2).toString());
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/service/SearchServiceTest.java b/src/test/java/mops/gruppen2/domain/service/SearchServiceTest.java
new file mode 100644
index 0000000..848bfe2
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/service/SearchServiceTest.java
@@ -0,0 +1,116 @@
+package mops.gruppen2.domain.service;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.Type;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+class SearchServiceTest {
+
+    private GroupCache groupCache;
+    private SearchService searchService;
+
+    @BeforeEach
+    void setUp() {
+        groupCache = new GroupCache(mock(EventStoreService.class));
+        searchService = new SearchService(groupCache);
+    }
+
+    @Test
+    void searchString_noResult() {
+        assertThat(searchService.searchString("", "TEST")).isEmpty();
+    }
+
+    @Test
+    void searchString_noResult_onePrivate_emptyString() {
+        GroupBuilder.get(groupCache, 1).group();
+
+        assertThat(searchService.searchString("", "TEST")).isEmpty();
+    }
+
+    @Test
+    void searchString_noResult_onePublic_emptyString_principalMember() {
+        GroupBuilder.get(groupCache, 1).group().testadmin().publik();
+
+        assertThat(searchService.searchString("", "TEST")).isEmpty();
+    }
+
+    @Test
+    void searchString_oneResult_onePublic_emptyString_principalNoMember() {
+        GroupBuilder.get(groupCache, 1).group().testadmin().publik();
+
+        assertThat(searchService.searchString("", "PETER")).hasSize(1);
+    }
+
+    @Test
+    void searchString_oneResult_multiple_emptyString() {
+        Group groupA = GroupBuilder.get(groupCache, 1).group().testadmin().lecture().build();
+        GroupBuilder.get(groupCache, 2).group().testadmin().publik().limit(2).add("PETER");
+        GroupBuilder.get(groupCache, 3).group().testadmin().publik().limit(2).add("PETER");
+        GroupBuilder.get(groupCache, 4).group().testadmin().privat();
+
+        assertThat(searchService.searchString("", "PETER")).containsExactly(groupA);
+        assertThat(searchService.searchString("", "TEST")).isEmpty();
+    }
+
+    @Test
+    void searchString_noPrivates() {
+        Group groupA = GroupBuilder.get(groupCache, 1).group().testadmin().lecture().build();
+        Group groupB = GroupBuilder.get(groupCache, 2).group().testadmin().publik().limit(2).add("PETER").build();
+        Group groupC = GroupBuilder.get(groupCache, 3).group().testadmin().publik().limit(2).add("PETER").build();
+        GroupBuilder.get(groupCache, 4).group().testadmin().privat();
+        GroupBuilder.get(groupCache, 5).group().testadmin().privat();
+        GroupBuilder.get(groupCache, 6).group().testadmin().privat();
+
+        assertThat(searchService.searchString("", "PETER")).containsExactly(groupA);
+        assertThat(searchService.searchString("", "PRRR")).containsOnly(groupA, groupB, groupC);
+        assertThat(searchService.searchString("", "TEST")).isEmpty();
+    }
+
+    @Test
+    void searchString_matchString_title() {
+        Group groupA = GroupBuilder.get(groupCache, 1).group().testadmin().lecture().title("A").build();
+        Group groupB = GroupBuilder.get(groupCache, 2).group().testadmin().lecture().title("B").build();
+        Group groupC = GroupBuilder.get(groupCache, 3).group().testadmin().lecture().title("C").build();
+        Group groupD = GroupBuilder.get(groupCache, 4).group().testadmin().lecture().title("CAESAR").build();
+
+        assertThat(searchService.searchString("C", "PETER")).containsExactly(groupC, groupD);
+        assertThat(searchService.searchString("C", "TEST")).isEmpty();
+    }
+
+    @Test
+    void searchString_matchString_desc() {
+        Group groupA = GroupBuilder.get(groupCache, 1).group().testadmin().lecture().desc("A").build();
+        Group groupB = GroupBuilder.get(groupCache, 2).group().testadmin().lecture().desc("B").build();
+        Group groupC = GroupBuilder.get(groupCache, 3).group().testadmin().lecture().desc("C").build();
+        Group groupD = GroupBuilder.get(groupCache, 4).group().testadmin().lecture().desc("CAESAR").build();
+
+        assertThat(searchService.searchString("C", "PETER")).containsExactly(groupC, groupD);
+        assertThat(searchService.searchString("C", "TEST")).isEmpty();
+    }
+
+    @Test
+    void searchType_noGroup() {
+        assertThat(searchService.searchType(Type.LECTURE, "PETER")).isEmpty();
+        assertThat(searchService.searchType(Type.PUBLIC, "PETER")).isEmpty();
+        assertThat(searchService.searchType(Type.PRIVATE, "PETER")).isEmpty();
+    }
+
+    @Test
+    void searchType_noPrivates() {
+        GroupBuilder.get(groupCache, 1).group().testadmin().lecture();
+        GroupBuilder.get(groupCache, 2).group().testadmin().publik();
+        GroupBuilder.get(groupCache, 3).group().testadmin().privat();
+        GroupBuilder.get(groupCache, 4).group().testadmin().privat();
+        GroupBuilder.get(groupCache, 5).group().testadmin().lecture();
+
+        assertThat(searchService.searchType(Type.LECTURE, "PETER")).hasSize(2);
+        assertThat(searchService.searchType(Type.PUBLIC, "PETER")).hasSize(1);
+        assertThat(searchService.searchType(Type.PRIVATE, "PETER")).isEmpty();
+    }
+}
diff --git a/src/test/java/mops/gruppen2/domain/service/helper/ProjectionHelperTest.java b/src/test/java/mops/gruppen2/domain/service/helper/ProjectionHelperTest.java
new file mode 100644
index 0000000..ced85a4
--- /dev/null
+++ b/src/test/java/mops/gruppen2/domain/service/helper/ProjectionHelperTest.java
@@ -0,0 +1,243 @@
+package mops.gruppen2.domain.service.helper;
+
+import mops.gruppen2.domain.event.AddMemberEvent;
+import mops.gruppen2.domain.event.CreateGroupEvent;
+import mops.gruppen2.domain.event.Event;
+import mops.gruppen2.domain.event.SetLimitEvent;
+import mops.gruppen2.domain.event.UpdateRoleEvent;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.model.group.Role;
+import mops.gruppen2.domain.model.group.User;
+import mops.gruppen2.domain.model.group.wrapper.Limit;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+
+import static mops.gruppen2.TestHelper.initEvents;
+import static mops.gruppen2.TestHelper.uuid;
+import static mops.gruppen2.domain.service.helper.ProjectionHelper.project;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+class ProjectionHelperTest {
+
+    @BeforeEach
+    void setUp() {
+    }
+
+    @Test
+    void project_nocache_emptyList() {
+        assertThat(project(Collections.emptyList())).isEmpty();
+    }
+
+    @Test
+    void project_nocache_oneCreate() {
+        List<Event> events = Arrays.asList(
+                new CreateGroupEvent(uuid(1), "TEST", LocalDateTime.now()));
+
+        initEvents(events);
+
+        assertThat(project(events)).hasSize(1);
+    }
+
+    @Test
+    void project_nocache_multipleCreate() {
+        List<Event> events = Arrays.asList(
+                new CreateGroupEvent(uuid(1), "TEST", LocalDateTime.now()),
+                new CreateGroupEvent(uuid(2), "TEST", LocalDateTime.now()),
+                new CreateGroupEvent(uuid(3), "TEST", LocalDateTime.now()),
+                new CreateGroupEvent(uuid(4), "TEST", LocalDateTime.now()),
+                new CreateGroupEvent(uuid(5), "TEST", LocalDateTime.now()));
+
+        events.get(0).init(1);
+        events.get(1).init(1);
+        events.get(2).init(1);
+        events.get(3).init(1);
+        events.get(4).init(1);
+
+        assertThat(project(events)).hasSize(5);
+    }
+
+    @Test
+    void project_nocache_oneDetailed() {
+        List<Event> events = Arrays.asList(
+                new CreateGroupEvent(uuid(1), "TEST", LocalDateTime.now()),
+                new AddMemberEvent(uuid(1), "TEST", "TEST", new User("TEST")),
+                new UpdateRoleEvent(uuid(1), "TEST", "TEST", Role.ADMIN),
+                new SetLimitEvent(uuid(1), "TEST", new Limit(5)));
+
+        initEvents(events);
+
+        List<Group> groups = project(events);
+
+        assertThat(groups).hasSize(1);
+        assertThat(groups.get(0).exists()).isTrue();
+        assertThat(groups.get(0).getAdmins()).hasSize(1);
+        assertThat(groups.get(0).getLimit()).isEqualTo(5);
+    }
+
+    @Test
+    void project_nocache_multipleDetailed() {
+        List<Event> eventsA = Arrays.asList(
+                new CreateGroupEvent(uuid(1), "TEST", LocalDateTime.now()),
+                new AddMemberEvent(uuid(1), "TEST", "TEST", new User("TEST")),
+                new UpdateRoleEvent(uuid(1), "TEST", "TEST", Role.ADMIN),
+                new SetLimitEvent(uuid(1), "TEST", new Limit(5)));
+
+        List<Event> eventsB = Arrays.asList(
+                new CreateGroupEvent(uuid(2), "TEST", LocalDateTime.now()),
+                new AddMemberEvent(uuid(2), "TEST", "TEST", new User("TEST")),
+                new UpdateRoleEvent(uuid(2), "TEST", "TEST", Role.ADMIN),
+                new SetLimitEvent(uuid(2), "TEST", new Limit(15)));
+
+        List<Event> eventsC = Arrays.asList(
+                new CreateGroupEvent(uuid(3), "TEST", LocalDateTime.now()),
+                new AddMemberEvent(uuid(3), "TEST", "TEST", new User("TEST")),
+                new UpdateRoleEvent(uuid(3), "TEST", "TEST", Role.ADMIN),
+                new SetLimitEvent(uuid(3), "TEST", new Limit(25)));
+
+        List<Event> eventsD = Arrays.asList(
+                new CreateGroupEvent(uuid(4), "TEST", LocalDateTime.now()),
+                new AddMemberEvent(uuid(4), "TEST", "TEST", new User("TEST")),
+                new UpdateRoleEvent(uuid(4), "TEST", "TEST", Role.ADMIN),
+                new SetLimitEvent(uuid(4), "TEST", new Limit(35)));
+
+        initEvents(eventsA);
+        initEvents(eventsB);
+        initEvents(eventsC);
+        initEvents(eventsD);
+
+        List<Event> events = new ArrayList<>();
+        events.addAll(eventsA);
+        events.addAll(eventsB);
+        events.addAll(eventsC);
+        events.addAll(eventsD);
+
+        List<Group> groups = project(events);
+
+        assertThat(groups).hasSize(4);
+        assertThat(groups.get(0).exists()).isTrue();
+        assertThat(groups.get(0).getAdmins()).hasSize(1);
+        assertThat(groups.get(0).getLimit()).isEqualTo(5);
+
+        assertThat(groups.get(1).exists()).isTrue();
+        assertThat(groups.get(1).getAdmins()).hasSize(1);
+        assertThat(groups.get(1).getLimit()).isEqualTo(15);
+
+        assertThat(groups.get(2).exists()).isTrue();
+        assertThat(groups.get(2).getAdmins()).hasSize(1);
+        assertThat(groups.get(2).getLimit()).isEqualTo(25);
+
+        assertThat(groups.get(3).exists()).isTrue();
+        assertThat(groups.get(3).getAdmins()).hasSize(1);
+        assertThat(groups.get(3).getLimit()).isEqualTo(35);
+    }
+
+    @Test
+    void project_cache_noGroups() {
+        Map<UUID, Group> groups = new HashMap<>();
+
+        project(groups, Collections.emptyList(), mock(GroupCache.class));
+
+        assertThat(groups).isEmpty();
+    }
+
+    @Test
+    void project_cache_oneCreate() {
+        Map<UUID, Group> groups = new HashMap<>();
+        List<Event> events = Arrays.asList(
+                new CreateGroupEvent(uuid(1), "TEST", LocalDateTime.now()));
+
+        initEvents(events);
+        project(groups, events, mock(GroupCache.class));
+
+        assertThat(groups).hasSize(1);
+        assertThat(groups.keySet()).containsExactly(uuid(1));
+    }
+
+    @Test
+    void project_cache_multipleCreate() {
+        Map<UUID, Group> groups = new HashMap<>();
+        List<Event> events = Arrays.asList(
+                new CreateGroupEvent(uuid(1), "TEST", LocalDateTime.now()),
+                new CreateGroupEvent(uuid(2), "TEST", LocalDateTime.now()),
+                new CreateGroupEvent(uuid(3), "TEST", LocalDateTime.now()),
+                new CreateGroupEvent(uuid(4), "TEST", LocalDateTime.now()));
+
+        events.get(0).init(1);
+        events.get(1).init(1);
+        events.get(2).init(1);
+        events.get(3).init(1);
+        project(groups, events, mock(GroupCache.class));
+
+        assertThat(groups).hasSize(4);
+        assertThat(groups.keySet()).containsExactly(uuid(1), uuid(2), uuid(3), uuid(4));
+    }
+
+    @Test
+    void project_cache_multipleDetailed() {
+        Map<UUID, Group> groups = new HashMap<>();
+        List<Event> eventsA = Arrays.asList(
+                new CreateGroupEvent(uuid(1), "TEST", LocalDateTime.now()),
+                new AddMemberEvent(uuid(1), "TEST", "TEST", new User("TEST")),
+                new UpdateRoleEvent(uuid(1), "TEST", "TEST", Role.ADMIN),
+                new SetLimitEvent(uuid(1), "TEST", new Limit(5)));
+
+        List<Event> eventsB = Arrays.asList(
+                new CreateGroupEvent(uuid(2), "TEST", LocalDateTime.now()),
+                new AddMemberEvent(uuid(2), "TEST", "TEST", new User("TEST")),
+                new UpdateRoleEvent(uuid(2), "TEST", "TEST", Role.ADMIN),
+                new SetLimitEvent(uuid(2), "TEST", new Limit(15)));
+
+        List<Event> eventsC = Arrays.asList(
+                new CreateGroupEvent(uuid(3), "TEST", LocalDateTime.now()),
+                new AddMemberEvent(uuid(3), "TEST", "TEST", new User("TEST")),
+                new UpdateRoleEvent(uuid(3), "TEST", "TEST", Role.ADMIN),
+                new SetLimitEvent(uuid(3), "TEST", new Limit(25)));
+
+        List<Event> eventsD = Arrays.asList(
+                new CreateGroupEvent(uuid(4), "TEST", LocalDateTime.now()),
+                new AddMemberEvent(uuid(4), "TEST", "TEST", new User("TEST")),
+                new UpdateRoleEvent(uuid(4), "TEST", "TEST", Role.ADMIN),
+                new SetLimitEvent(uuid(4), "TEST", new Limit(35)));
+
+        initEvents(eventsA);
+        initEvents(eventsB);
+        initEvents(eventsC);
+        initEvents(eventsD);
+
+        List<Event> events = new ArrayList<>();
+        events.addAll(eventsA);
+        events.addAll(eventsB);
+        events.addAll(eventsC);
+        events.addAll(eventsD);
+
+        project(groups, events, mock(GroupCache.class));
+
+        assertThat(groups).hasSize(4);
+        assertThat(groups.get(uuid(1)).exists()).isTrue();
+        assertThat(groups.get(uuid(1)).getAdmins()).hasSize(1);
+        assertThat(groups.get(uuid(1)).getLimit()).isEqualTo(5);
+
+        assertThat(groups.get(uuid(2)).exists()).isTrue();
+        assertThat(groups.get(uuid(2)).getAdmins()).hasSize(1);
+        assertThat(groups.get(uuid(2)).getLimit()).isEqualTo(15);
+
+        assertThat(groups.get(uuid(3)).exists()).isTrue();
+        assertThat(groups.get(uuid(3)).getAdmins()).hasSize(1);
+        assertThat(groups.get(uuid(3)).getLimit()).isEqualTo(25);
+
+        assertThat(groups.get(uuid(4)).exists()).isTrue();
+        assertThat(groups.get(uuid(4)).getAdmins()).hasSize(1);
+        assertThat(groups.get(uuid(4)).getLimit()).isEqualTo(35);
+    }
+}
diff --git a/src/test/java/mops/gruppen2/infrastructure/GroupCacheTest.java b/src/test/java/mops/gruppen2/infrastructure/GroupCacheTest.java
new file mode 100644
index 0000000..8031301
--- /dev/null
+++ b/src/test/java/mops/gruppen2/infrastructure/GroupCacheTest.java
@@ -0,0 +1,312 @@
+package mops.gruppen2.infrastructure;
+
+import mops.gruppen2.GroupBuilder;
+import mops.gruppen2.domain.exception.GroupNotFoundException;
+import mops.gruppen2.domain.model.group.Group;
+import mops.gruppen2.domain.service.EventStoreService;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import static mops.gruppen2.TestHelper.uuid;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+// Kann nur indirket über events getestet werden, diese werden also "mitgetestet"
+class GroupCacheTest {
+
+    private GroupCache cache;
+
+    @BeforeEach
+    void setUp() {
+        cache = new GroupCache(Mockito.mock(EventStoreService.class));
+    }
+
+    @Test
+    void groups_noGroups() {
+        assertThat(cache.groups()).isEmpty();
+    }
+
+    @Test
+    void group_groupNotFound() {
+        assertThatThrownBy(() -> cache.group(uuid(1)))
+                .isInstanceOf(GroupNotFoundException.class);
+    }
+
+    @Test
+    void group_linkNotFound() {
+        assertThatThrownBy(() -> cache.group("00000000-0000-0000-0000-000000000000"))
+                .isInstanceOf(GroupNotFoundException.class);
+    }
+
+    @Test
+    void group_groupFound() {
+        Group group = GroupBuilder.get(cache, 1).group().build();
+
+        assertThat(cache.group(uuid(1))).isEqualTo(group);
+    }
+
+    @Test
+    void group_linkFound() {
+        Group group = GroupBuilder.get(cache, 1).group().build();
+
+        assertThat(cache.group(group.getLink())).isEqualTo(group);
+    }
+
+    @Test
+    void userGroups_noGroups() {
+        assertThat(cache.userGroups("TEST")).isEmpty();
+    }
+
+    @Test
+    void userGroups_noUserGroups() {
+        Group group = GroupBuilder.get(cache, 1).group().add("PETER").build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userGroups("TEST")).isEmpty();
+    }
+
+    @Test
+    void userGroups_oneUserGroup() {
+        Group group = GroupBuilder.get(cache, 1).group().add("TEST").build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userGroups("TEST")).containsExactly(group);
+    }
+
+    @Test
+    void userGroups_userGroup_multiple() {
+        Group groupA = GroupBuilder.get(cache, 1).group().add("TEST").build();
+        Group groupB = GroupBuilder.get(cache, 2).group().add("PETER").build();
+        Group groupC = GroupBuilder.get(cache, 3).group().add("TEST").build();
+        Group groupD = GroupBuilder.get(cache, 4).group().add("PETER").build();
+
+        assertThat(cache.groups()).hasSize(4);
+        assertThat(cache.userGroups("PETER")).containsExactly(groupB, groupD);
+    }
+
+    @Test
+    void userLectures_noGroups() {
+        assertThat(cache.userLectures("PETER")).isEmpty();
+    }
+
+    @Test
+    void userLectures_noLecture() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().publik().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userLectures("PETER")).isEmpty();
+    }
+
+    @Test
+    void userLectures_oneLecture() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().limit(2).add("PETER").lecture().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userLectures("PETER")).containsExactly(group);
+    }
+
+    @Test
+    void userLectures_lecture_multiple() {
+        Group groupA = GroupBuilder.get(cache, 1).group().testadmin().limit(2).add("PETER").lecture().build();
+        Group groupB = GroupBuilder.get(cache, 2).group().testadmin().limit(2).add("PETER").publik().build();
+        Group groupC = GroupBuilder.get(cache, 3).group().testadmin().limit(2).add("PETER").privat().build();
+        Group groupD = GroupBuilder.get(cache, 4).group().testadmin().lecture().build();
+
+        assertThat(cache.groups()).hasSize(4);
+        assertThat(cache.userLectures("PETER")).containsExactly(groupA);
+    }
+
+    @Test
+    void userPublics_noGroups() {
+        assertThat(cache.userPublics("PETER")).isEmpty();
+    }
+
+    @Test
+    void userPublics_noPublic() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().limit(2).add("PETER").publik().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userLectures("PETER")).isEmpty();
+    }
+
+    @Test
+    void userPublics_onePublic() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().limit(2).add("PETER").lecture().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userLectures("PETER")).containsExactly(group);
+    }
+
+    @Test
+    void userPublics_public_multiple() {
+        Group groupA = GroupBuilder.get(cache, 1).group().testadmin().limit(2).add("PETER").lecture().build();
+        Group groupB = GroupBuilder.get(cache, 2).group().testadmin().limit(2).add("PETER").publik().build();
+        Group groupC = GroupBuilder.get(cache, 3).group().testadmin().limit(2).add("PETER").privat().build();
+        Group groupD = GroupBuilder.get(cache, 4).group().testadmin().publik().build();
+
+        assertThat(cache.groups()).hasSize(4);
+        assertThat(cache.userPublics("PETER")).containsExactly(groupB);
+    }
+
+    @Test
+    void userPrivates_noGroups() {
+        assertThat(cache.userPrivates("PETER")).isEmpty();
+    }
+
+    @Test
+    void userPrivates_noPrivate() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().limit(2).add("PETER").publik().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userPrivates("PETER")).isEmpty();
+    }
+
+    @Test
+    void userPrivates_onePrivate() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().limit(2).add("PETER").privat().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userPrivates("PETER")).containsExactly(group);
+    }
+
+    @Test
+    void userPrivates_private_multiple() {
+        Group groupA = GroupBuilder.get(cache, 1).group().testadmin().limit(2).add("PETER").lecture().build();
+        Group groupB = GroupBuilder.get(cache, 2).group().testadmin().limit(2).add("PETER").privat().build();
+        Group groupC = GroupBuilder.get(cache, 3).group().testadmin().privat().build();
+        Group groupD = GroupBuilder.get(cache, 4).group().testadmin().publik().build();
+
+        assertThat(cache.groups()).hasSize(4);
+        assertThat(cache.userPrivates("PETER")).containsExactly(groupB);
+    }
+
+    @Test
+    void publics_noGroups() {
+        assertThat(cache.publics()).isEmpty();
+    }
+
+    @Test
+    void publics_noPublic() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().privat().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.publics()).isEmpty();
+    }
+
+    @Test
+    void publics_onePublic() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().publik().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.publics()).containsExactly(group);
+    }
+
+    @Test
+    void publics_public_multiple() {
+        Group groupA = GroupBuilder.get(cache, 1).group().testadmin().lecture().build();
+        Group groupB = GroupBuilder.get(cache, 2).group().testadmin().privat().build();
+        Group groupC = GroupBuilder.get(cache, 3).group().testadmin().privat().build();
+        Group groupD = GroupBuilder.get(cache, 4).group().testadmin().publik().build();
+
+        assertThat(cache.groups()).hasSize(4);
+        assertThat(cache.publics()).containsExactly(groupD);
+    }
+
+    @Test
+    void privates_noGroups() {
+        assertThat(cache.privates()).isEmpty();
+    }
+
+    @Test
+    void privates_noPrivate() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().publik().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.privates()).isEmpty();
+    }
+
+    @Test
+    void privates_onePrivate() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().privat().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.privates()).containsExactly(group);
+    }
+
+    @Test
+    void privates_private_multiple() {
+        Group groupA = GroupBuilder.get(cache, 1).group().testadmin().lecture().build();
+        Group groupB = GroupBuilder.get(cache, 2).group().testadmin().privat().build();
+        Group groupC = GroupBuilder.get(cache, 3).group().testadmin().privat().build();
+        Group groupD = GroupBuilder.get(cache, 4).group().testadmin().publik().build();
+
+        assertThat(cache.groups()).hasSize(4);
+        assertThat(cache.privates()).containsExactly(groupB, groupC);
+    }
+
+    @Test
+    void lectures_noGroups() {
+        assertThat(cache.lectures()).isEmpty();
+    }
+
+    @Test
+    void lectures_noLecture() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().privat().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.lectures()).isEmpty();
+    }
+
+    @Test
+    void lectures_oneLecture() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().lecture().build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.lectures()).containsExactly(group);
+    }
+
+    @Test
+    void lectures_lecture_multiple() {
+        Group groupA = GroupBuilder.get(cache, 1).group().testadmin().lecture().build();
+        Group groupB = GroupBuilder.get(cache, 2).group().testadmin().privat().build();
+        Group groupC = GroupBuilder.get(cache, 3).group().testadmin().lecture().build();
+        Group groupD = GroupBuilder.get(cache, 4).group().testadmin().publik().build();
+
+        assertThat(cache.groups()).hasSize(4);
+        assertThat(cache.lectures()).containsExactly(groupA, groupC);
+    }
+
+    //Indirekt: void usersPut() {}
+
+    @Test
+    void usersRemove() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().lecture().limit(2).add("PETER").kick("PETER").build();
+
+        assertThat(cache.groups()).hasSize(1);
+        assertThat(cache.userLectures("PETER")).isEmpty();
+    }
+
+    //Indirekt: void groupsPut() {}
+
+    @Test
+    void groupsRemove() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().lecture().destroy().build();
+
+        assertThat(cache.groups()).hasSize(0);
+    }
+
+
+    //Indirekt: void linksPut() {}
+
+    @Test
+    void linksRemove() {
+        Group group = GroupBuilder.get(cache, 1).group().testadmin().lecture().link(2).build();
+
+        assertThat(cache.group(String.valueOf(uuid(2)))).isEqualTo(group);
+    }
+
+    //Indirekt: void typesPut() {}
+
+    //Indirekt: void typesRemove() {}
+}
diff --git a/src/test/java/mops/gruppen2/infrastructure/controller/APIControllerTest.java b/src/test/java/mops/gruppen2/infrastructure/controller/APIControllerTest.java
new file mode 100644
index 0000000..e4cbf27
--- /dev/null
+++ b/src/test/java/mops/gruppen2/infrastructure/controller/APIControllerTest.java
@@ -0,0 +1,53 @@
+package mops.gruppen2.infrastructure.controller;
+
+import mops.gruppen2.domain.service.EventStoreService;
+import mops.gruppen2.infrastructure.GroupCache;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+import org.springframework.security.test.context.support.WithMockUser;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+class APIControllerTest {
+
+    private EventStoreService store;
+    private GroupCache cache;
+    private APIController controller;
+
+    @BeforeEach
+    void setUp() {
+        store = mock(EventStoreService.class);
+        cache = new GroupCache(store);
+        controller = new APIController(cache, store);
+    }
+
+    @WithMockUser("ROLE_api_user")
+    @Test
+    void getApiUpdate_noEvents() {
+        when(store.findMaxEventId()).thenReturn(0L);
+
+        assertThat(controller.getApiUpdate(0).getVersion()).isZero();
+        assertThat(controller.getApiUpdate(0).getGroups()).isEmpty();
+    }
+
+    @Disabled
+    @WithMockUser("ROLE_api_user")
+    @Test
+    void getApiUpdate_noUpdate() {
+    }
+
+    @Disabled
+    @WithMockUser("ROLE_api_user")
+    @Test
+    void getApiUserGroups() {
+    }
+
+    @Disabled
+    @WithMockUser("ROLE_api_user")
+    @Test
+    void getApiGroup() {
+    }
+}
diff --git a/src/test/java/mops/gruppen2/infrastructure/controller/GroupCreationControllerTest.java b/src/test/java/mops/gruppen2/infrastructure/controller/GroupCreationControllerTest.java
new file mode 100644
index 0000000..4d01119
--- /dev/null
+++ b/src/test/java/mops/gruppen2/infrastructure/controller/GroupCreationControllerTest.java
@@ -0,0 +1,19 @@
+package mops.gruppen2.infrastructure.controller;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class GroupCreationControllerTest {
+
+    @BeforeEach
+    void setUp() {
+    }
+
+    @Test
+    void getCreate() {
+    }
+
+    @Test
+    void postCreateOrga() {
+    }
+}
diff --git a/src/test/java/mops/gruppen2/infrastructure/controller/GroupDetailsControllerTest.java b/src/test/java/mops/gruppen2/infrastructure/controller/GroupDetailsControllerTest.java
new file mode 100644
index 0000000..42c7a9c
--- /dev/null
+++ b/src/test/java/mops/gruppen2/infrastructure/controller/GroupDetailsControllerTest.java
@@ -0,0 +1,67 @@
+package mops.gruppen2.infrastructure.controller;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class GroupDetailsControllerTest {
+
+    @BeforeEach
+    void setUp() {
+    }
+
+    @Test
+    void getDetailsPage() {
+    }
+
+    @Test
+    void postDetailsJoin() {
+    }
+
+    @Test
+    void postDetailsLeave() {
+    }
+
+    @Test
+    void getDetailsHistory() {
+    }
+
+    @Test
+    void getDetailsExportHistoryPlain() {
+    }
+
+    @Test
+    void getDetailsExportHistorySql() {
+    }
+
+    @Test
+    void getDetailsExportMembers() {
+    }
+
+    @Test
+    void getDetailsEdit() {
+    }
+
+    @Test
+    void postDetailsEditMeta() {
+    }
+
+    @Test
+    void postDetailsEditUserLimit() {
+    }
+
+    @Test
+    void postDetailsEditCsv() {
+    }
+
+    @Test
+    void postDetailsEditRole() {
+    }
+
+    @Test
+    void postDetailsEditDelete() {
+    }
+
+    @Test
+    void postDetailsEditDestroy() {
+    }
+}
diff --git a/src/test/java/mops/gruppen2/infrastructure/controller/SearchAndInviteControllerTest.java b/src/test/java/mops/gruppen2/infrastructure/controller/SearchAndInviteControllerTest.java
new file mode 100644
index 0000000..edc1ad0
--- /dev/null
+++ b/src/test/java/mops/gruppen2/infrastructure/controller/SearchAndInviteControllerTest.java
@@ -0,0 +1,31 @@
+package mops.gruppen2.infrastructure.controller;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class SearchAndInviteControllerTest {
+
+    @BeforeEach
+    void setUp() {
+    }
+
+    @Test
+    void getSearch() {
+    }
+
+    @Test
+    void postSearchString() {
+    }
+
+    @Test
+    void getSearchAll() {
+    }
+
+    @Test
+    void getSearchType() {
+    }
+
+    @Test
+    void getJoin() {
+    }
+}