Added tests for permission denied exception handler

tests/Flarum/Api/Handler/PermissionDeniedExceptionHandlerTest.php

@@ -0,0 +1,30 @@
+<?php
+namespace Tests\Flarum\Api\Handler;
+
+use Flarum\Api\Handler\PermissionDeniedExceptionHandler;
+use Flarum\Core\Exception\PermissionDeniedException;
+use Tests\Test\TestCase;
+
+class PermissionDeniedExceptionHandlerTest extends TestCase
+{
+    private $handler;
+
+    public function init()
+    {
+        $this->handler = new PermissionDeniedExceptionHandler;
+    }
+
+    public function test_it_handles_recognisable_exceptions()
+    {
+        $this->assertFalse($this->handler->manages(new \Exception));
+        $this->assertTrue($this->handler->manages(new PermissionDeniedException));
+    }
+
+    public function test_managing_exceptions()
+    {
+        $response = $this->handler->handle(new PermissionDeniedException);
+
+        $this->assertEquals(401, $response->getStatus());
+        $this->assertEquals([[]], $response->getErrors());
+    }
+}