public async Task Can_Register_User() { //arrange var mock = new Mock <IAccountMongoService>(); var userService = new AccountMongoController(mock.Object); var user = new RegisterModel { Email = "*****@*****.**", Password = "******", ConfirmPassword = "******" }; //act await userService.Register(user); //assert mock.Verify(c => c.RegisterUser(It.Is <RegisterModel>(s => s.Email == "*****@*****.**")), Times.Once()); Assert.Equal("*****@*****.**", user.Email); }