final String environmentKey = "environmentKey";
final String accessSecret = "accessSecret";
final SpreedlyInvoker spreedlyInvoker = new SpreedlyInvoker(environmentKey, accessSecret, client);
final String targetUrl = "http://target.url";
final String method = "POST";
final Transaction transaction = new Transaction();
final PaymentMethod returnPaymentMethod = new PaymentMethod();
//set up mocks
final WebTarget webTarget = mock(WebTarget.class);
when(client.target(targetUrl)).thenReturn(webTarget);