@Test
public void testValidatePublicKeysNull() throws IOException {

    
    Path path = Paths.get("src/test/resources/athenz.instanceid.csr");
    String csr = new String(Files.readAllBytes(path));
    
    X509CertRequest certReq = new X509CertRequest(csr);
    assertNotNull(certReq);
    
    assertFalse(certReq.validatePublicKeys((String) null));
}