Update request options to exclude multipart when irrelevant

CONTRIBUTING.md

@@ -25,7 +25,11 @@ We accept contributions via Pull Requests on [Github](https://github.com/stevenm
 ## Running Tests
 
 ``` bash
-$ phpunit
+$ ./vendor/bin/phpunit
+```
+
+``` bash
+$ ./vendor/bin/phpcs src --standard=psr2 -sp
 ```
 
 

src/Http.php

@@ -161,6 +161,25 @@ private function getRequestExceptionParts(RequestException $requestException)
         return $parts;
     }
 
+    /**
+     * Creates an array of request options based on the current status of the
+     * http client.
+     *
+     * @return array
+     */
+    protected function getRequestOptions()
+    {
+        $options = [
+            'proxy' => Configuration::get('proxy')
+        ];
+
+        if (!empty(array_filter($this->multipartResources))) {
+            $options['multipart'] = $this->multipartResources;
+        }
+
+        return $options;
+    }
+
     /**
      * Creates fully qualified domain from given path.
      *
@@ -230,10 +249,10 @@ protected function queueResourceAs($name, $resource)
     protected function sendRequest(RequestInterface $request)
     {
         try {
-            $response = $this->httpClient->send($request, [
-                'multipart' => $this->multipartResources,
-                'proxy' => Configuration::get('proxy')
-            ]);
+            $response = $this->httpClient->send(
+                $request,
+                $this->getRequestOptions()
+            );
 
             $this->multipartResources = [];