public function testEnsureNonJsonIsntCached()
 {
     $pp = new PP('http://example.com');
     $pp->with_cache('file')->directory(static::$cache_directory);
     $pp->prepare();
     // Simulate the events for the cache object.
     $request = new Request('GET', 'http://foo.com');
     $response = new Response(200, array(), 'Foo');
     // Fake the request.
     $pp->cache_plugin->onRequestBeforeSend(new Event(array('request' => $request)));
     // Fake the response to that request.
     $pp->cache_plugin->onRequestSent(new Event(array('request' => $request, 'response' => $response)));
     $key_provider = new \Guzzle\Plugin\Cache\DefaultCacheKeyProvider();
     $data = $pp->cache_object->fetch($key_provider->getCacheKey($request));
     $this->assertEmpty($data, "Non json responses should not be cached.");
 }