public void Should_return_false_when_not_all_user_guess_is_digital_and_length_is_not_4(string userGuess)
        {
            // given
            UserGuessValidator userGuessValidator = new UserGuessValidator();
            // when
            bool validateResult = userGuessValidator.Validate(userGuess);

            // then
            Assert.False(validateResult);
        }
        public void Should_return_true_when_user_guess_4_digitals_seperated_with_space(string userGuess)
        {
            // given
            UserGuessValidator userGuessValidator = new UserGuessValidator();
            // when
            bool validateResult = userGuessValidator.Validate(userGuess);

            // then
            Assert.True(validateResult);
        }