public void Should_expect_email_with_valid_format()
        {
            // Arrange
            var validator = new RegisterUserCommandValidator();
            var command   = new RegisterUserCommand("wrongEmail.com", "P@ssw0rd");

            // Act
            var validationResult = validator.Validate(command);

            // Assert
            validationResult.Errors.Should().ContainSingle().Which.ErrorMessage.Should().Be("An email with a correct format is required.");
        }
        public void Should_not_allow_null_password()
        {
            // Arrange
            var validator = new RegisterUserCommandValidator();
            var command   = new RegisterUserCommand("*****@*****.**", null);

            // Act
            var validationResult = validator.Validate(command);

            // Assert
            validationResult.Errors.Should().ContainSingle().Which.ErrorMessage.Should().Be("A password is required.");
        }
        public void Should_not_allow_null_email()
        {
            // Arrange
            var validator = new RegisterUserCommandValidator();
            var command   = new RegisterUserCommand(null, "P@ssw0rd");

            // Act
            var validationResult = validator.Validate(command);

            // Assert
            validationResult.Errors.Should().ContainSingle().Which.ErrorMessage.Should().Be("An email is required.");
        }