Test gateway via Echo API request

src/Gateway.php

@@ -5,6 +5,7 @@
 use Omnipay\Common\AbstractGateway;
 use Omnipay\Common\Exception\InvalidResponseException;
 use Omnipay\Csob\Message\CompletePurchaseRequest;
+use Omnipay\Csob\Message\EchoRequest;
 use Omnipay\Csob\Message\InitPaymentRequest;
 use Omnipay\Csob\Message\ProcessPaymentRequest;
 use Omnipay\Csob\Message\PaymentResponse;
@@ -124,6 +125,30 @@ public function completePurchase(array $parameters = array())
         return $this->createRequest(CompletePurchaseRequest::class, $parameters);
     }
 
+    /**
+     * @param string $merchantId
+     * @param string $httpMethod
+     * @return Message\EchoResponse
+     * @throws \Exception
+     * @see https://github.com/csob/paymentgateway/wiki/eAPI-1.5-EN#getpost-httpsapiplatebnibranacsobczapiv15echo-
+     */
+    public function testGateway($merchantId, $httpMethod = 'GET')
+    {
+        $data = [
+            'merchantId' => $merchantId,
+            'dttm' => date('Ymdhis'),
+        ];
+
+        /** @var EchoRequest $request */
+        $request = $this->createRequest(EchoRequest::class, $data);
+        if ($httpMethod === 'POST') {
+            $response = $request->sendViaPost();
+        } else {
+            $response = $request->sendViaGet();
+        }
+        return $response;
+    }
+
     protected function createRequest($class, array $parameters)
     {
         if (!($this->signator instanceof DataSignator)) {

src/Message/EchoRequest.php

@@ -0,0 +1,103 @@
+<?php
+
+namespace Omnipay\Csob\Message;
+
+use Guzzle\Http\Message\RequestInterface;
+use Omnipay\Common\Message\ResponseInterface;
+
+class EchoRequest extends AbstractRequest
+{
+    public function setMerchantId($value)
+    {
+        $this->setParameter('merchantId', $value);
+    }
+
+    public function setDttm($value)
+    {
+        $this->setParameter('dttm', $value);
+    }
+
+    /**
+     * Get the raw data array for this message. The format of this varies from gateway to
+     * gateway, but will usually be either an associative array, or a SimpleXMLElement.
+     *
+     * @return mixed
+     */
+    public function getData()
+    {
+        $data = [
+            "merchantId" => $this->getParameter('merchantId'),
+            "dttm" => $this->getParameter('dttm'),
+        ];
+        $data['signature'] = $this->signData($data);
+        return $data;
+    }
+
+    private function signData($data)
+    {
+        $arrayKeys = [
+            'merchantId', 'dttm',
+        ];
+        return $this->getSignator()->sign($data, $arrayKeys);
+    }
+
+    /**
+     * Send the request with specified data
+     *
+     * @param  mixed $data The data to send
+     * @return ResponseInterface
+     */
+    public function sendData($data)
+    {
+        return $this->sendViaPost();
+    }
+
+    public function sendViaPost()
+    {
+        $apiUrl = $this->getApiUrl() . '/echo';
+        $data = json_encode($this->getData());
+
+        $httpRequest = $this->httpClient->createRequest(
+            RequestInterface::POST,
+            $apiUrl,
+            ['Content-Type' => 'application/json'],
+            $data
+        );
+
+        return $this->response = $this->sendAndProcessResponse($httpRequest);
+    }
+
+    public function sendViaGet()
+    {
+        $data = $this->getData();
+        $apiUrl = implode('/', [
+            $this->getApiUrl(),
+            'echo',
+            $data['merchantId'],
+            $data['dttm'],
+            urlencode($data['signature']),
+        ]);
+
+        $httpRequest = $this->httpClient->createRequest(
+            RequestInterface::GET,
+            $apiUrl
+        );
+
+        return $this->response = $this->sendAndProcessResponse($httpRequest);
+    }
+
+    /**
+     * @param RequestInterface $httpRequest
+     * @return EchoResponse
+     */
+    private function sendAndProcessResponse(RequestInterface $httpRequest)
+    {
+        $httpResponse = $httpRequest->send();
+        $data = $httpResponse->json();
+
+        $response = new EchoResponse($this, $data);
+        $response->setVerifier($this->getVerifier());
+
+        return $response;
+    }
+}

src/Message/EchoResponse.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Omnipay\Csob\Message;
+
+class EchoResponse extends AbstractResponse
+{
+
+}