public void ReturnsUserObjectIfPasswordDoesMatchSpecifiedPassword()
            {
                // Arrange
                var svc = CreateService();
                var expected = new User() { Email = "*****@*****.**",  Password = "******", PasswordSalt="salt"};
                svc.Data.Users.Add(expected);
                svc.Data.SaveChanges();

                // Act
                var actual = svc.LogIn("*****@*****.**", "password");

                // Assert
                Assert.Equal(expected, actual);
            }
            public void ReturnsNullIfUserPasswordDoesNotMatchSpecifiedPassword()
            {
                // Arrange
                var svc = CreateService();
                var expected = new User() { Email = "*****@*****.**", Password = "******", PasswordSalt = "salt" };
                svc.Data.Users.Add(expected);
                svc.Data.SaveChanges();

                // Act
                var actual = svc.LogIn("*****@*****.**", "abc123");

                // Assert
                Assert.Null(actual);
            }