Organize test suites into unit and integration

This is the goals of project organization composing different
combinations to run any number of tests together.

tests/integration/CreatesApplication.php

@@ -0,0 +1,47 @@
+<?php
+/**
+ * CreatesApplication.php
+ * Copyright (c) 2019 james@firefly-iii.org
+ *
+ * This file is part of Firefly III (https://github.com/firefly-iii).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+declare(strict_types=1);
+
+namespace Tests\integration;
+
+use Illuminate\Contracts\Console\Kernel;
+use Illuminate\Foundation\Application;
+
+/**
+ * Trait CreatesApplication
+ *
+ */
+trait CreatesApplication
+{
+    /**
+     * Creates the application.
+     *
+     * @return Application
+     */
+    public function createApplication()
+    {
+        $app = require __DIR__ . '/../bootstrap/app.php';
+
+        $app->make(Kernel::class)->bootstrap();
+
+        return $app;
+    }
+}