[BUGFIX] Empty JSON-Content will be added to request

If you create an POST-Request (e.g. with an forking action) the HTTPClient
will be created with a post content "[]".
This can create some problems on requesting path.

Solution: Check if the content is empty.

Author: andygrunwald

lib/Github/HttpClient/HttpClient.php

@@ -167,7 +167,9 @@ public function request($path, array $parameters = array(), $httpMethod = 'GET',
 
         $request = $this->createRequest($httpMethod, $path);
         $request->addHeaders($headers);
-        $request->setContent(json_encode($parameters));
+        if (count($parameters) > 0) {
+            $request->setContent(json_encode($parameters));
+        }
 
         $hasListeners = 0 < count($this->listeners);
         if ($hasListeners) {

test/Github/Tests/HttpClient/HttpClientTest.php

@@ -84,6 +84,23 @@ public function shouldDoPOSTRequest()
 
         $httpClient = new HttpClient(array(), $client);
         $httpClient->post($path, $parameters, $headers);
+
+        $this->assertEquals('{"a":"b"}', $httpClient->getLastRequest()->getContent());
+    }
+
+    /**
+     * @test
+     */
+    public function shouldDoPOSTRequestWithoutContent()
+    {
+        $path       = '/some/path';
+
+        $client = $this->getBrowserMock();
+
+        $httpClient = new HttpClient(array(), $client);
+        $httpClient->post($path);
+
+        $this->assertEmpty($httpClient->getLastRequest()->getContent());
     }
 
     /**