@Test
public void validate() throws Exception {

  assertTrue(instance.validate(null, null, null, null, null, null));
  assertTrue(instance.validate(null, true, null, null, null, null));
  assertFalse(instance.validate(null, false, null, null, null, null));
  assertTrue(instance.validate("", null, null, null, null, null));
  assertFalse(instance.validate("????", null, null, null, null, null));
  assertTrue(instance.validate("qrvM3e7_", null, null, null, null, null));
  assertTrue(instance.validate("qrvM3e7_", null, 6, null, null, null));
  assertFalse(instance.validate("qrvM3e7_", null, 5, null, null, null));
}