public void RepoEnsureICanAddANewUser() { List <ProviderUser> emptyDB = new List <ProviderUser>(); //This is the empty database table ConnectMocksToDataStore(emptyDB); mock_set_users.Setup(i => i.Add(It.IsAny <ProviderUser>())).Callback((ProviderUser s) => emptyDB.Add(s)); bool added = repo.AddNewUser(test_user); ProviderUser stock_user = repo.GetAllUsers().Where(u => u.RealUser.Id == test_user.Id).SingleOrDefault(); Assert.IsNotNull(stock_user); Assert.IsTrue(added); Assert.AreEqual(1, repo.GetAllUsers().Count); }