MAGETWO-35076: Impossible to place order with DHL EU shipping method

- CR Changes

Author: Pechenushko

app/code/Magento/Dhl/Model/Carrier.php

@@ -1034,7 +1034,7 @@ protected function _parseResponse($response)
 
         if (strlen(trim($response)) > 0) {
             if (strpos(trim($response), '<?xml') === 0) {
-                $xml = $this->parseXml($response);
+                $xml = $this->parseXml($response, 'Magento\Shipping\Model\Simplexml\Element');
                 if (is_object($xml)) {
                     if (in_array($xml->getName(), ['ErrorResponse', 'ShipmentValidateErrorResponse'])
                         || isset($xml->GetQuoteResponse->Note->Condition)
@@ -1775,7 +1775,7 @@ protected function _parseXmlTrackingResponse($trackings, $response)
         $resultArr = [];
 
         if (strlen(trim($response)) > 0) {
-            $xml = $this->parseXml($response);
+            $xml = $this->parseXml($response, 'Magento\Shipping\Model\Simplexml\Element');
             if (!is_object($xml)) {
                 $errorTitle = __('Response is in the wrong format');
             }

app/code/Magento/Fedex/Model/Carrier.php

@@ -706,7 +706,7 @@ protected function _parseXmlResponse($response)
         $priceArr = [];
 
         if (strlen(trim($response)) > 0) {
-            $xml = $this->parseXml($response);
+            $xml = $this->parseXml($response, 'Magento\Shipping\Model\Simplexml\Element');
             if (is_object($xml)) {
                 if (is_object($xml->Error) && is_object($xml->Error->Message)) {
                     $errorTitle = (string)$xml->Error->Message;

app/code/Magento/Shipping/Model/Carrier/AbstractCarrierOnline.php

@@ -612,10 +612,12 @@ public function getMethodPrice($cost, $method = '')
      * Parse XML string and return XML document object or false
      *
      * @param string $xmlContent
-     * @return \Magento\Shipping\Model\Simplexml\Element|bool
+     * @param string $customSimplexml
+     *
+     * @return \SimpleXMLElement|bool
      */
-    public function parseXml($xmlContent)
+    public function parseXml($xmlContent, $customSimplexml = 'SimpleXMLElement')
     {
-        return simplexml_load_string($xmlContent, 'Magento\Shipping\Model\Simplexml\Element');
+        return simplexml_load_string($xmlContent, $customSimplexml);
     }
 }

app/code/Magento/Shipping/Test/Unit/Model/Carrier/AbstractCarrierOnlineTest.php

@@ -111,5 +111,8 @@ public function testParseXml()
         $simpleXmlElement = $this->carrier->parseXml($xmlString);
         $this->assertEquals('GetResponse', $simpleXmlElement->getName());
         $this->assertEquals(42, (int)$simpleXmlElement->value);
+        $this->assertInstanceOf('SimpleXMLElement', $simpleXmlElement);
+        $customSimpleXmlElement = $this->carrier->parseXml($xmlString, 'Magento\Shipping\Model\Simplexml\Element');
+        $this->assertInstanceOf('Magento\Shipping\Model\Simplexml\Element', $customSimpleXmlElement);
     }
 }

app/code/Magento/Usps/Model/Carrier.php

@@ -512,7 +512,7 @@ protected function _parseXmlResponse($response)
                         $response
                     );
                 }
-                $xml = $this->parseXml($response);
+                $xml = $this->parseXml($response, 'Magento\Shipping\Model\Simplexml\Element');
 
                 if (is_object($xml)) {
                     $allowedMethods = explode(',', $this->getConfigData('allowed_methods'));
@@ -1042,7 +1042,7 @@ protected function _parseXmlTrackingResponse($trackingvalue, $response)
         $resultArr = [];
         if (strlen(trim($response)) > 0) {
             if (strpos(trim($response), '<?xml') === 0) {
-                $xml = $this->parseXml($response);
+                $xml = $this->parseXml($response, 'Magento\Shipping\Model\Simplexml\Element');
                 if (is_object($xml)) {
                     if (isset($xml->Number) && isset($xml->Description) && (string)$xml->Description != '') {
                         $errorTitle = (string)$xml->Description;
@@ -1869,7 +1869,7 @@ protected function _doShipmentRequest(\Magento\Framework\Object $request)
         $client->setParameterGet('XML', $requestXml);
         $response = $client->request()->getBody();
 
-        $response = $this->parseXml($response);
+        $response = $this->parseXml($response, 'Magento\Shipping\Model\Simplexml\Element');
         if ($response === false || $response->getName() == 'Error') {
             $debugData['result'] = [
                 'error' => $response->Description,