@Test
public void testAddUserToCertificateFailedIfEmptyUserDetails() {

    CertificateUser certUser = new CertificateUser("testuser1", "read", "certificatename.t-mobile.com", "internal");
    userDetails = null;
    ResponseEntity<String> responseEntityExpected = ResponseEntity.status(HttpStatus.BAD_REQUEST).body("{\"errors\":[\"Access denied: No permission to add users to this certificate\"]}");
    ResponseEntity<String> responseEntity = sSLCertificateService.addUserToCertificate(certUser, null, false);
    assertEquals(HttpStatus.BAD_REQUEST, responseEntity.getStatusCode());
    assertEquals(responseEntityExpected, responseEntity);
}