added migs refund support

src/Message/ThreePartyRefundRequest.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace Omnipay\Migs\Message;
+
+use Omnipay\Common\Exception\InvalidRequestException;
+
+/**
+ * Migs Complete Purchase Request
+ */
+class ThreePartyRefundRequest extends AbstractRequest
+{
+    protected $action = 'refund';
+    public function getData()
+    {
+        $this->validate('amount', 'returnUrl', 'transactionId');
+        $data = $this->getBaseData();
+        $data['vpc_SecureHash']  = $this->calculateHash($data);
+        $data['vpc_TransNo'] = $this->getParameter('transactionNo');
+        $data['vpc_User']  = $this->getUser();
+        $data['vpc_Password']  = $this->getPassword();
+        return $data;
+    }
+
+    public function sendData($data)
+    {
+        $httpResponse = $this->httpClient->post($this->getEndpoint(), null, $data)->send();
+
+        return $this->response = new Response($this, $httpResponse->getBody());
+    }
+
+    public function getEndpoint()
+    {
+        return $this->endpoint.'vpcdps';
+    }
+}

src/ThreePartyGateway.php

@@ -23,4 +23,9 @@ public function completePurchase(array $parameters = array())
     {
         return $this->createRequest('\Omnipay\Migs\Message\ThreePartyCompletePurchaseRequest', $parameters);
     }
+
+    public function refund(array $parameters = array())
+    {
+        return $this->createRequest('\Omnipay\Migs\Message\ThreePartyRefundRequest', $parameters);
+    }
 }

tests/ThreePartyGatewayTest.php

@@ -36,4 +36,14 @@ public function testCompletePurchase()
 
         $this->assertSame('10.00', $request->getAmount());
     }
+
+    public function testRefund()
+    {
+        $request = $this->gateway->refund(array('amount' => '10.00', 'transactionNo' => '1112'));
+
+        $this->assertInstanceOf('\Omnipay\Migs\Message\ThreePartyRefundRequest', $request);
+
+        $this->assertSame('10.00', $request->getAmount());
+    }
+
 }