### Question:
GithubLinkValidator implements ConstraintValidator<GithubLink, String> { public boolean isValid(String link, ConstraintValidatorContext context) { return StringUtils.isEmpty(link) || link.matches(regex); } GithubLinkValidator(); void initialize(GithubLink constraint); boolean isValid(String link, ConstraintValidatorContext context);  }### Answer:
@Test public void illegalNotGithub() throws Exception { assertThat( validator.isValid("https: ).isFalse(); }
@Test public void illegalInvalidGithub() throws Exception { assertThat( validator.isValid("https: ).isFalse(); }
@Test public void validGithubLink() throws Exception { assertThat( validator.isValid("https: ).isTrue(); }