Added muc tests

tests/test_muc.c

@@ -0,0 +1,18 @@
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <cmocka.h>
+#include <stdlib.h>
+
+#include "muc.h"
+
+void test_muc_add_invite(void **state)
+{
+    char *room = "room@conf.server";
+    muc_init();
+    muc_add_invite(room);
+    
+    gboolean invite_exists = muc_invites_include(room);
+
+    assert_true(invite_exists);
+}