@Test
public void testTokenValidateNullSignature() throws CryptoException {

    PrincipalToken token = new PrincipalToken.Builder(svcVersion, svcDomain, svcName)
        .host(host).salt(salt).expirationWindow(expirationTime).build();
    
    assertFalse(token.validate(servicePublicKeyStringK0, 3600, false));
    assertFalse(token.validate(servicePublicKeyStringK0, 3600, false, null));
    StringBuilder errMsg = new StringBuilder();
    assertFalse(token.validate(servicePublicKeyStringK0, 3600, false, errMsg));
    assertTrue(!errMsg.toString().isEmpty());
}