Use the 2.4 default tests directory structure

tests/CreatesApplication.php

+<?php
+
+namespace Tests;
+
+use Illuminate\Contracts\Console\Kernel;
+
+trait CreatesApplication
+{
+    /**
+     * Creates the application.
+     *
+     * @return \Illuminate\Foundation\Application
+     */
+    public function createApplication()
+    {
+        $app = require __DIR__.'/../bootstrap/app.php';
+
+        $app->make(Kernel::class)->bootstrap();
+
+        return $app;
+    }
+}

tests/ExampleTest.php → tests/Feature/ExampleTest.php

 <?php
 
+namespace Tests\Feature;
+
+use Tests\TestCase;
 use Illuminate\Foundation\Testing\WithoutMiddleware;
 use Illuminate\Foundation\Testing\DatabaseMigrations;
 use Illuminate\Foundation\Testing\DatabaseTransactions;
@@ -7,13 +10,14 @@ use Illuminate\Foundation\Testing\DatabaseTransactions;
 class ExampleTest extends TestCase
 {
     /**
-     * A basic functional test example.
+     * A basic test example.
      *
      * @return void
      */
-    public function testBasicExample()
+    public function testBasicTest()
     {
-        $this->visit('/')
-             ->see('Laravel 5');
+        $response = $this->get('/');
+
+        $response->assertStatus(200);
     }
 }

tests/TestCase.php

 <?php
 
-class TestCase extends Illuminate\Foundation\Testing\TestCase
-{
-    /**
-     * The base URL to use while testing the application.
-     *
-     * @var string
-     */
-    protected $baseUrl = 'http://localhost';
-
-    /**
-     * Creates the application.
-     *
-     * @return \Illuminate\Foundation\Application
-     */
-    public function createApplication()
-    {
-        $app = require __DIR__.'/../bootstrap/app.php';
+namespace Tests;
 
-        $app->make(Illuminate\Contracts\Console\Kernel::class)->bootstrap();
+use Illuminate\Foundation\Testing\TestCase as BaseTestCase;
 
-        return $app;
-    }
+abstract class TestCase extends BaseTestCase
+{
+    use CreatesApplication;
 }

tests/Unit/ExampleTest.php

+<?php
+
+namespace Tests\Unit;
+
+use Tests\TestCase;
+use Illuminate\Foundation\Testing\DatabaseMigrations;
+use Illuminate\Foundation\Testing\DatabaseTransactions;
+
+class ExampleTest extends TestCase
+{
+    /**
+     * A basic test example.
+     *
+     * @return void
+     */
+    public function testBasicTest()
+    {
+        $this->assertTrue(true);
+    }
+}