Add support for draft PRs (#820)

* Add support for draft PRs #807

* Use acceptHeadervalue from the AcceptHeaderTrait

* Fix test for PullRequest

* Use strict equivalence in PullRequest

* Remove unused headers var in PullRequest

Author: ktoth2

doc/pull_requests.md

@@ -54,6 +54,7 @@ The ``$pullRequest`` array contains the same elements as every entry in the resu
 
 A pull request can either be created by supplying both the Title & Body, OR an Issue ID.
 Details regarding the content of parameters 3 and 4 of the ``create``.
+You can create a draft pull request by adding a parameter with key `draft` and value `true`.
 
 #### Populated with Title and Body
 

lib/Github/Api/PullRequest.php

@@ -156,6 +156,11 @@ public function create($username, $repository, array $params)
             throw new MissingArgumentException(['issue', 'body']);
         }
 
+        if (isset($params['draft']) && $params['draft'] === true) {
+            //This feature is in preview mode, so set the correct accept-header
+            $this->acceptHeaderValue = 'application/vnd.github.shadow-cat-preview+json';
+        }
+
         return $this->post('/repos/'.rawurlencode($username).'/'.rawurlencode($repository).'/pulls', $params);
     }
 

test/Github/Tests/Api/PullRequestTest.php

@@ -260,6 +260,27 @@ public function shouldCreatePullRequestUsingIssueId()
         $api->create('ezsystems', 'ezpublish', $data);
     }
 
+    /**
+     * @test
+     */
+    public function shouldCreateDraftPullRequest()
+    {
+        $data = [
+            'base'  => 'master',
+            'head'  => 'virtualtestbranch',
+            'title' => 'TITLE: Testing draft pull-request creation from PHP Github API',
+            'body'  => 'BODY: Testing draft pull-request creation from PHP Github API',
+            'draft' => 'true',
+        ];
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('post')
+            ->with('/repos/ezsystems/ezpublish/pulls', $data);
+
+        $api->create('ezsystems', 'ezpublish', $data);
+    }
+
     /**
      * @test
      */