[Core][Mock] Make sure we signal that $bodyDownloaded=true (#958)

Author: Nyholm

src/Test/ResultMockFactory.php

@@ -263,10 +263,15 @@ private static function getResponseObject(): Response
     {
         $reflectionClass = new \ReflectionClass(Response::class);
         $response = $reflectionClass->newInstanceWithoutConstructor();
+
         $property = $reflectionClass->getProperty('resolveResult');
         $property->setAccessible(true);
         $property->setValue($response, true);
 
+        $property = $reflectionClass->getProperty('bodyDownloaded');
+        $property->setAccessible(true);
+        $property->setValue($response, true);
+
         return $response;
     }
 }