Changes according to feedback

Author: Nyholm

src/CachePlugin.php

@@ -2,6 +2,7 @@
 
 namespace Http\Client\Plugin;
 
+use Http\Client\Utils\Promise\FulfilledPromise;
 use Psr\Cache\CacheItemPoolInterface;
 use Psr\Http\Message\RequestInterface;
 use Psr\Http\Message\ResponseInterface;
@@ -62,7 +63,7 @@ public function handleRequest(RequestInterface $request, callable $next, callabl
 
         if ($cacheItem->isHit()) {
             // return cached response
-            return $cacheItem->get();
+            return new FulfilledPromise($cacheItem->get());
         }
 
         return $next($request)->then(function (ResponseInterface $response) use ($cacheItem) {
@@ -83,7 +84,7 @@ public function handleRequest(RequestInterface $request, callable $next, callabl
      *
      * @return bool
      */
-    private function isCacheable(ResponseInterface $response)
+    protected function isCacheable(ResponseInterface $response)
     {
         if (!in_array($response->getStatusCode(), array(200, 203, 300, 301, 302, 404, 410))) {
             return false;