fixes namespace and adds test

Author: bshaffer

src/Google/Http/REST.php

@@ -18,9 +18,9 @@
 use Google\Auth\HttpHandler\HttpHandlerFactory;
 use GuzzleHttp\ClientInterface;
 use GuzzleHttp\Exception\RequestException;
+use GuzzleHttp\Psr7\Response;
 use Psr\Http\Message\RequestInterface;
 use Psr\Http\Message\ResponseInterface;
-use Psr\Http\Message\Response;
 
 /**
  * This class implements the RESTful transport of apiServiceRequest()'s

tests/Google/Http/RESTTest.php

@@ -70,6 +70,14 @@ public function testDecode500ResponseThrowsException()
     $this->rest->decodeHttpResponse($response, $this->request);
   }
 
+  /** @expectedException Google_Service_Exception */
+  public function testExceptionResponse()
+  {
+    $http = new GuzzleHttp\Client();
+
+    $request = new Request('GET', 'http://httpbin.org/status/500');
+    $response = $this->rest->doExecute($http, $request);
+  }
 
   public function testDecodeEmptyResponse()
   {