public void RemovesUserFromRoom() { var repository = new InMemoryRepository(); var user = new ChatUser { Name = "foo" }; repository.Add(user); var room = new ChatRoom { Name = "Room" }; room.Users.Add(user); user.Rooms.Add(room); var service = new ChatService(repository); service.LeaveRoom(user, room); Assert.False(user.Rooms.Contains(room)); Assert.False(room.Users.Contains(user)); }