adds a few additional api controller tests (#1429)

* added CreatePostControllerTest

* added DeleteDiscussionControllerTest

* added ListDiscussionControllerTest

* Apply fixes from StyleCI

[ci skip] [skip ci]

tests/Api/Controller/DeleteDiscussionControllerTest.php

@@ -0,0 +1,43 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Tests\Api\Controller;
+
+use Flarum\Api\Controller\DeleteDiscussionController;
+use Flarum\Discussion\Discussion;
+use Flarum\Tests\Test\Concerns\RetrievesAuthorizedUsers;
+
+class DeleteDiscussionControllerTest extends ApiControllerTestCase
+{
+    use RetrievesAuthorizedUsers;
+
+    protected $controller = DeleteDiscussionController::class;
+    protected $discussion;
+
+    protected function init()
+    {
+        $this->discussion = Discussion::start(__CLASS__, $this->getNormalUser());
+
+        $this->discussion->save();
+    }
+
+    /**
+     * @test
+     */
+    public function admin_can_delete()
+    {
+        $this->actor = $this->getAdminUser();
+
+        $response = $this->callWith([], ['id' => $this->discussion->id]);
+
+        $this->assertEquals(204, $response->getStatusCode());
+    }
+}