refactor: Split FrontController into multiple classes

Closes #177

tests/JsonControllerTest.php

@@ -0,0 +1,63 @@
+<?php
+/**
+ * JsonControllerTest class.
+ */
+
+namespace Alltube\Test;
+
+use Alltube\Config;
+use Alltube\Controller\JsonController;
+use Alltube\LocaleManager;
+use Alltube\ViewFactory;
+use Exception;
+use Slim\Container;
+use Slim\Http\Environment;
+use Slim\Http\Request;
+use Slim\Http\Response;
+
+/**
+ * Unit tests for the FrontController class.
+ */
+class JsonControllerTest extends ControllerTest
+{
+
+    /**
+     * Prepare tests.
+     */
+    protected function setUp()
+    {
+        parent::setUp();
+
+        $this->controller = new JsonController($this->container);
+    }
+
+    /**
+     * Test the json() function.
+     *
+     * @return void
+     */
+    public function testJson()
+    {
+        $this->assertRequestIsOk('json', ['url' => 'https://www.youtube.com/watch?v=M7IpKCZ47pU']);
+    }
+
+    /**
+     * Test the json() function with an error.
+     *
+     * @return void
+     */
+    public function testJsonWithError()
+    {
+        $this->assertRequestIsServerError('json', ['url' => 'http://example.com/foo']);
+    }
+
+    /**
+     * Test the json() function without the URL parameter.
+     *
+     * @return void
+     */
+    public function testJsonWithoutUrl()
+    {
+        $this->assertRequestIsClientError('json');
+    }
+}