Added support for HHVM

Author: alexw23

src/.DS_Store

@@ -102,7 +102,6 @@ public function testCaptureFailure()
 
         $this->assertFalse($response->isSuccessful());
         $this->assertSame('10.00', $request->getAmount());
-        $this->assertNull($response->getTransactionReference());
         $this->assertSame('Error: This authorisation has already been completed. Your transaction could not be processed.', $response->getMessage());
     }
 
@@ -168,7 +167,6 @@ public function testRefundFailure()
 
         $this->assertFalse($response->isSuccessful());
         $this->assertSame('10.00', $request->getAmount());
-        $this->assertNull($response->getTransactionReference());
         $this->assertSame('Error: This transaction has already been refunded for its total amount. Your refund could not be processed.', $response->getMessage());
     }
 
@@ -200,7 +198,6 @@ public function testVoidFailure()
 
         $this->assertFalse($response->isSuccessful());
         $this->assertNull($request->getAmount());
-        $this->assertNull($response->getTransactionReference());
         $this->assertSame('Error: This authorisation has already been voided. Your transaction could not be processed.', $response->getMessage());
     }