Only include the ReferrerID if it is set to a non-empty string.

Author: judgej

src/Message/DirectAuthorizeRequest.php

@@ -26,7 +26,10 @@ protected function getBaseAuthorizeData()
         $data['ClientIPAddress'] = $this->getClientIp();
         $data['ApplyAVSCV2'] = $this->getApplyAVSCV2() ?: 0;
         $data['Apply3DSecure'] = $this->getApply3DSecure() ?: 0;
-        $data['ReferrerID'] = $this->getReferrerId();
+
+        if ($this->getReferrerId()) {
+            $data['ReferrerID'] = $this->getReferrerId();
+        }
 
         // billing details
         $data['BillingFirstnames'] = $card->getBillingFirstName();

tests/Message/DirectAuthorizeRequestTest.php

@@ -52,6 +52,16 @@ public function testGetData()
         $this->assertSame('3F7A4119-8671-464F-A091-9E59EB47B80C', $data['ReferrerID']);
     }
 
+    public function testGetDataNoReferrerId()
+    {
+        // Default value is equivalent to this:
+        $this->request->setReferrerId('');
+
+        $data = $this->request->getData();
+
+        $this->assertArrayNotHasKey('ReferrerID', $data);
+    }
+
     public function testGetDataCustomerDetails()
     {
         $card = $this->request->getCard();