chore: throw an exception when no serializer is provided to the controller (#3614)

* chore: throw an exception when no serializer is provided to the controller

Signed-off-by: Sami Mazouz <ilyasmazouz@gmail.com>

* test: no serializer set throws exception

Signed-off-by: Sami Mazouz <sychocouldy@gmail.com>

Signed-off-by: Sami Mazouz <ilyasmazouz@gmail.com>
Signed-off-by: Sami Mazouz <sychocouldy@gmail.com>

framework/core/tests/integration/api/AbstractSerializeControllerTest.php

@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Tests\integration\api;
+
+use Flarum\Api\Controller\AbstractSerializeController;
+use Flarum\Extend;
+use Flarum\Testing\integration\TestCase;
+use Psr\Http\Message\ServerRequestInterface;
+use Tobscure\JsonApi\Document;
+use Tobscure\JsonApi\SerializerInterface;
+
+class AbstractSerializeControllerTest extends TestCase
+{
+    public function test_missing_serializer_class_throws_exception()
+    {
+        $this->extend(
+            (new Extend\Routes('api'))
+                ->get('/dummy-serialize', 'dummy-serialize', DummySerializeController::class)
+        );
+
+        $response = $this->send(
+            $this->request('GET', '/api/dummy-serialize')
+        );
+
+        $json = json_decode((string) $response->getBody(), true);
+
+        $this->assertEquals(500, $response->getStatusCode());
+        $this->assertStringStartsWith('InvalidArgumentException: Serializer required for controller: '.DummySerializeController::class, $json['errors'][0]['detail']);
+    }
+}
+
+class DummySerializeController extends AbstractSerializeController
+{
+    public $serializer = null;
+
+    protected function data(ServerRequestInterface $request, Document $document)
+    {
+        return [];
+    }
+
+    protected function createElement($data, SerializerInterface $serializer)
+    {
+        return $data;
+    }
+}