Omnipay\Common\Message\AbstractRequest::send PHP Method

    public function send()
    {
        $data = $this->getData();
        return $this->sendData($data);
    }

 public function testSendError()
 {
     $this->setMockHttpResponse('CaptureFailure.txt');
     $response = $this->request->send();
     $this->assertFalse($response->isSuccessful());
     $this->assertFalse($response->isRedirect());
     $this->assertSame('Failure', $response->getMessage());
 }