### Question:
UUIDValidator implements ConstraintValidator<ValidUUID, String> { @Override public boolean isValid(String uuid, ConstraintValidatorContext context) { return pattern.matcher(uuid).matches(); }  @Override void initialize(ValidUUID constraint); @Override boolean isValid(String uuid, ConstraintValidatorContext context);  }### Answer:
@Test public void shouldBeValidUUID() { Assertions.assertThat(validator.isValid("3a1757d0-cc9c-44cd-aee4-a5c0fd54d41b", null)).isTrue(); }
@Test public void shouldBeInvalidUUID() { Assertions.assertThat(validator.isValid("3a1757d0", null)).isFalse(); }