@Test
public void testPrincipalNameValidationInvalid() {

    
    assertFalse(Validate.principalName("user:john%doe"));
    assertFalse(Validate.principalName("user.user:john.doe."));
    assertFalse(Validate.principalName("user.user.:john.doe"));
    assertFalse(Validate.principalName(".user:doe"));
    assertFalse(Validate.principalName(".doe"));
    assertFalse(Validate.principalName(":doe"));
    assertFalse(Validate.principalName("doe:"));
    assertFalse(Validate.principalName("::doe"));
    assertFalse(Validate.principalName("doe::"));
    assertFalse(Validate.principalName("user:john:doe"));
    assertFalse(Validate.principalName(null));
    assertFalse(Validate.principalName(""));
}