public function testJsonMarshalling()
 {
     $errorResponse = new ErrorResponse();
     $errorResponse->errorId = '123';
     $apiError = new APIError();
     $apiError->code = '1';
     $apiError->message = 'Test message';
     $apiError->propertyName = 'test';
     $errorResponse->errors = array($apiError);
     $jsonErrorResponse = $errorResponse->toJson();
     $this->assertEquals($jsonErrorResponse, json_encode($errorResponse));
     $actualErrorResponse = new ErrorResponse();
     $actualErrorResponse->fromJson($jsonErrorResponse);
     $this->assertEquals($errorResponse, $actualErrorResponse);
 }