diff --git a/src/main/java/mops/gruppen2/domain/Group.java b/src/main/java/mops/gruppen2/domain/Group.java
index 26ed5a5..03eb2fb 100644
--- a/src/main/java/mops/gruppen2/domain/Group.java
+++ b/src/main/java/mops/gruppen2/domain/Group.java
@@ -68,12 +68,13 @@ public class Group extends Aggregate {
         this.description = event.getNewGroupDescription();
     }
 
-    private void applyEvent(DeleteUserEvent event) {
-        for (User user : members) {
-            if (user.getUser_id().equals(event.getUser_id())) {
-                this.members.remove(user);
-                break;
-            }
+    private void applyEvent(DeleteUserEvent event) throws UserNotFoundException{
+        User user = new User(event.getUser_id(), "","","");
+
+        if (this.members.contains(user)) {
+            this.members.remove(user);
+        } else {
+            throw new UserNotFoundException("Nutzer wurde nicht gefunden!");
         }
     }
 }
diff --git a/src/test/java/mops/gruppen2/domain/GroupTest.java b/src/test/java/mops/gruppen2/domain/GroupTest.java
index c81e2cf..65906bc 100644
--- a/src/test/java/mops/gruppen2/domain/GroupTest.java
+++ b/src/test/java/mops/gruppen2/domain/GroupTest.java
@@ -66,7 +66,7 @@ class GroupTest {
         });
 
 
-        //assertThat(group.getMembers().size()).isEqualTo(1);
+        assertThat(group.getMembers().size()).isEqualTo(1);
     }
 
     @Test
@@ -84,6 +84,19 @@ class GroupTest {
         assertThat(group.getMembers().size()).isEqualTo(0);
     }
 
+    @Test
+    void deleteUserThatDoesNotExists() throws Exception{
+        CreateGroupEvent createGroupEvent = new CreateGroupEvent(1, 2, "Prof", "Tolle Gruppe", "Tolle Beshreibung");
+        Group group = new Group();
+        group.applyEvent(createGroupEvent);
+
+        DeleteUserEvent deleteUserEvent = new DeleteUserEvent(3, 2, "Prof");
+
+        Assertions.assertThrows(UserNotFoundException.class, () ->{
+            group.applyEvent(deleteUserEvent);
+        });
+    }
+
     // Verwendet CreateGroupEvent und AddUserEvent
     @Test
     void updateRoleForExistingUser() throws Exception{