assertTrue(validator.isValid("   ", context));
        assertTrue(validator.isValid("\t", context));
        assertTrue(validator.isValid("\n", context));
    }

    @Test
    public void test_isValid_emptyValue() {
        final ConstraintValidatorContext context = null;
        assertTrue(validator.isValid("", context));
    }

    @Test
    public void test_determineValid_nullAndBlank() {