start using PHPUnit and test all this

tests/ApplicationTest.php

@@ -0,0 +1,56 @@
+<?php
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 magdev
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author    magdev
+ * @copyright 2019 Marco Grätsch
+ * @package   magdev/dossier
+ * @license   http://opensource.org/licenses/MIT MIT License
+ */
+ 
+namespace Magdev\DossierTests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Magdev\Dossier\Application;
+use Magdev\Dossier\Service\GitService;
+
+class ApplicationTest extends TestCase
+{
+    private $app = null;
+    
+    public function setup(): void
+    {
+        $this->app = new Application();
+    }
+    
+    public function testGetContainer()
+    {
+        $this->assertInstanceOf(ContainerBuilder::class, $this->app->getContainer());
+    }
+    
+    public function testGetValidService()
+    {
+        $this->assertInstanceOf(GitService::class, $this->app->getService('git'));
+    }
+}