Allow Empty POST data

This PR allows the SDK, using CURL, to send a POST requests even
when the POST data is not present.

Previously, the SDK would issue a GET request even when ::post was
called when the payload was empty.

src/Request/CURL.php

@@ -28,6 +28,7 @@ class CURL implements \Moltin\SDK\RequestInterface
     public $header;
 
     protected $curl;
+    protected $options = array();
 
     public function setup($url, $method, $post = array(), $token = null)
     {
@@ -36,9 +37,7 @@ public function setup($url, $method, $post = array(), $token = null)
         $this->curl = curl_init();
         $this->url = $url;
         $this->method = $method;
-
-        // Add request settings
-        curl_setopt_array($this->curl, array(
+        $this->options = array(
             CURLOPT_URL => $url,
             CURLOPT_CUSTOMREQUEST => $method,
             CURLOPT_HEADER => false,
@@ -48,15 +47,16 @@ public function setup($url, $method, $post = array(), $token = null)
             CURLOPT_SSL_VERIFYPEER => false,
             CURLOPT_TIMEOUT => 40,
             CURLINFO_HEADER_OUT => true,
-        ));
+        );
+
+        if ('POST' == $method) {
+            $this->options[CURLOPT_POST] = true;
+        }
 
         // Add post
         if (!empty($post)) {
             $post = $this->toFormattedPostData($post, $_FILES);
-
-            // Assign to curl
-            curl_setopt($this->curl, CURLOPT_POST, true);
-            curl_setopt($this->curl, CURLOPT_POSTFIELDS, $post);
+            $this->options[CURLOPT_POSTFIELDS] = $post;
         }
 
         // Add auth header
@@ -78,7 +78,7 @@ public function setup($url, $method, $post = array(), $token = null)
         $headers[] = 'X-Moltin-Session: '.session_id();
 
         // Set headers
-        curl_setopt($this->curl, CURLOPT_HTTPHEADER, $headers);
+        $this->options[CURLOPT_HTTPHEADER] = $headers;
     }
 
     /**
@@ -115,6 +115,7 @@ protected function generateInlineArray($value, $key = '', $index = '') {
     public function make()
     {
         // Make request
+        curl_setopt_array($this->curl, $this->options);
         $result = curl_exec($this->curl);
         $this->code = curl_getinfo($this->curl, CURLINFO_HTTP_CODE);
         $this->time = curl_getinfo($this->curl, CURLINFO_TOTAL_TIME);

tests/Request/CURLTest.php

@@ -23,6 +23,24 @@ public function test_inline_arrays_to_formatted_post_data($data, $expected) {
         $this->assertEquals($expected, $result);
     }
 
+    public function test_that_empty_post_data_creates_post_request()
+    {
+        $request = $this->newCurlInstance();
+        $request->setup('/checkout/payment/authorize', 'POST');
+        $options = \PHPUnit_Framework_Assert::readAttribute($request, 'options');
+        $this->assertArrayHasKey(CURLOPT_POST, $options);
+        $this->assertEquals(true, $options[CURLOPT_POST]);
+
+        $request = $this->newCurlInstance();
+        $post = array('foo' => 'bar');
+        $request->setup('/checkout/payment/authorize', 'POST', $post);
+        $options = \PHPUnit_Framework_Assert::readAttribute($request, 'options');
+        $this->assertArrayHasKey(CURLOPT_POST, $options);
+        $this->assertArrayHasKey(CURLOPT_POSTFIELDS, $options);
+        $this->assertEquals(true, $options[CURLOPT_POST]);
+        $this->assertEquals($post, $options[CURLOPT_POSTFIELDS]);
+    }
+
     public function getOrderInlineArrayPostDataProvider()
     {
         $dataOrder = array(