Add internal tests for socket apis (#1900)

core/iwasm/libraries/lib-socket/test/nslookup.c

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2023 Amazon.com Inc. or its affiliates. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#include <assert.h>
+#include <string.h>
+#ifdef __wasi__
+#include <wasi/api.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <wasi_socket_ext.h>
+#else
+#include <netdb.h>
+#endif
+
+void
+test_nslookup(int af)
+{
+    struct addrinfo *res;
+    int count = 0;
+    struct addrinfo hints;
+    char *url = "google-public-dns-a.google.com";
+
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = af;
+    hints.ai_socktype = SOCK_STREAM;
+    int ret = getaddrinfo(url, 0, &hints, &res);
+    assert(ret == 0);
+    struct addrinfo *address = res;
+    while (address) {
+        assert(address->ai_family == af);
+        assert(address->ai_socktype == SOCK_STREAM);
+        count++;
+        address = address->ai_next;
+    }
+
+    assert(count > 0);
+    freeaddrinfo(res);
+}
+
+int
+main()
+{
+    test_nslookup(AF_INET);  /* for ipv4 */
+    test_nslookup(AF_INET6); /* for ipv6 */
+
+    return 0;
+}