diff --git a/tests/TestCase.php b/tests/TestCase.php
new file mode 100644
index 0000000..789c4ed
--- /dev/null
+++ b/tests/TestCase.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace Tests;
+
+use DI\Container;
+use PHLAK\Config\Config;
+use PHPUnit\Framework\TestCase as PHPUnitTestCase;
+
+class TestCase extends PHPUnitTestCase
+{
+    /** @var Container The test container */
+    protected $container;
+
+    /** @var Config The test config */
+    protected $config;
+
+    /** @var string Path to test files directory */
+    protected $testFilesPath = __DIR__ . '/files';
+
+    /**
+     * This method is called before each test.
+     *
+     * @return void
+     */
+    public function setUp(): void
+    {
+        $this->container = new Container();
+        $this->container->set('app.root', $this->testFilesPath);
+
+        $this->config = new Config([
+            'app' => [
+                'sort_order' => 'type',
+                'reverse_sort' => false,
+                'hidden_files' => [],
+                'hide_app_files' => true,
+                'hide_vcs_files' => false,
+                'max_hash_size' => 1000000000,
+            ],
+        ]);
+    }
+}
diff --git a/tests/Unit/Bootstrap/ConfigComposerTest.php b/tests/Unit/Bootstrap/ConfigComposerTest.php
index a106d6c..3ef2ca4 100644
--- a/tests/Unit/Bootstrap/ConfigComposerTest.php
+++ b/tests/Unit/Bootstrap/ConfigComposerTest.php
@@ -3,18 +3,16 @@
 namespace Tests\Unit\Bootstrap;
 
 use App\Bootstrap\ConfigComposer;
-use DI\Container;
 use PHLAK\Config\Config;
-use PHPUnit\Framework\TestCase;
+use Tests\TestCase;
 
 class ConfigComposerTest extends TestCase
 {
-    public function test_it_can_compose_the_config_component()
+    public function test_it_can_compose_the_config_component(): void
     {
-        $container = new Container();
-        (new ConfigComposer($container))();
+        (new ConfigComposer($this->container))();
 
-        $config = $container->get(Config::class);
+        $config = $this->container->get(Config::class);
 
         $this->assertInstanceOf(Config::class, $config);
         $this->assertTrue($config->has('app'));
diff --git a/tests/Unit/Bootstrap/FinderComposerTest.php b/tests/Unit/Bootstrap/FinderComposerTest.php
index 7a8b50c..6e212f5 100644
--- a/tests/Unit/Bootstrap/FinderComposerTest.php
+++ b/tests/Unit/Bootstrap/FinderComposerTest.php
@@ -3,37 +3,13 @@
 namespace Tests\Unit\Bootstrap;
 
 use App\Bootstrap\FinderComposer;
-use DI\Container;
-use PHLAK\Config\Config;
-use PHPUnit\Framework\TestCase;
 use RuntimeException;
 use Symfony\Component\Finder\Finder;
 use Symfony\Component\Finder\SplFileInfo;
+use Tests\TestCase;
 
 class FinderComposerTest extends TestCase
 {
-    /** @var Container The application container */
-    protected $container;
-
-    /** @var Config The application config */
-    protected $config;
-
-    public function setUp(): void
-    {
-        $this->container = new Container();
-        $this->container->set('app.root', realpath(__DIR__ . '/../../files'));
-
-        $this->config = new Config([
-            'app' => [
-                'sort_order' => 'type',
-                'reverse_sort' => false,
-                'hidden_files' => [],
-                'hide_app_files' => true,
-                'hide_vcs_files' => false,
-            ]
-        ]);
-    }
-
     public function test_it_can_compose_the_finder_component(): void
     {
         (new FinderComposer($this->container, $this->config))();
@@ -67,7 +43,7 @@ class FinderComposerTest extends TestCase
         ], $this->getFilesArray($finder));
     }
 
-    public function test_it_can_reverse_the_sort_order()
+    public function test_it_can_reverse_the_sort_order(): void
     {
         $this->config->set('app.reverse_sort', true);
 
diff --git a/tests/Unit/Bootstrap/ViewComposerTest.php b/tests/Unit/Bootstrap/ViewComposerTest.php
index f413a97..0c496ba 100644
--- a/tests/Unit/Bootstrap/ViewComposerTest.php
+++ b/tests/Unit/Bootstrap/ViewComposerTest.php
@@ -4,19 +4,17 @@ namespace Tests\Unit\Bootstrap;
 
 use App\Bootstrap\ViewComposer;
 use App\Bootstrap\ViewFunctions;
-use DI\Container;
 use PHLAK\Config\Config;
-use PHPUnit\Framework\TestCase;
 use Slim\Views\Twig;
+use Tests\TestCase;
 
 class ViewComposerTest extends TestCase
 {
-    public function test_it_can_compose_the_view_component()
+    public function test_it_can_compose_the_view_component(): void
     {
-        $container = new Container();
-        (new ViewComposer($container, new Config))();
+        (new ViewComposer($this->container, new Config))();
 
-        $twig = $container->get(Twig::class);
+        $twig = $this->container->get(Twig::class);
 
         $this->assertInstanceOf(Twig::class, $twig);
         $this->assertEquals('app/cache/views', $twig->getEnvironment()->getCache());
diff --git a/tests/Unit/Controllers/DirectoryControllerTest.php b/tests/Unit/Controllers/DirectoryControllerTest.php
index 38f36e0..bdcde64 100644
--- a/tests/Unit/Controllers/DirectoryControllerTest.php
+++ b/tests/Unit/Controllers/DirectoryControllerTest.php
@@ -2,31 +2,33 @@
 
 namespace Tests\Controllers;
 
+use App\Bootstrap\ViewComposer;
 use App\Controllers\DirectoryController;
-use DI\Container;
-use PHLAK\Config\Config;
-use PHPUnit\Framework\TestCase;
 use Psr\Http\Message\ResponseInterface;
 use Slim\Psr7\Response;
 use Slim\Views\Twig;
 use Symfony\Component\Finder\Finder;
+use Tests\TestCase;
 
 class DirectoryControllerTest extends TestCase
 {
-    public function test_it_returns_a_response()
+    public function test_it_returns_a_response(): void
     {
+        $this->container->call(ViewComposer::class);
+
         $controller = new DirectoryController(
-            $this->createMock(Container::class),
-            $this->createMock(Config::class),
-            $this->createMock(Twig::class)
+            $this->container,
+            $this->config,
+            $this->container->get(Twig::class)
         );
 
         $response = $controller(
-            $this->createMock(Finder::class),
+            new Finder(),
             new Response(),
             'tests/files'
         );
 
         $this->assertInstanceOf(ResponseInterface::class, $response);
+        $this->assertEquals(200, $response->getStatusCode());
     }
 }
diff --git a/tests/Unit/Controllers/FileInfoControllerTest.php b/tests/Unit/Controllers/FileInfoControllerTest.php
index 828b948..1e2f23e 100644
--- a/tests/Unit/Controllers/FileInfoControllerTest.php
+++ b/tests/Unit/Controllers/FileInfoControllerTest.php
@@ -3,26 +3,13 @@
 namespace Tests\Unit\Controllers;
 
 use App\Controllers\FileInfoController;
-use PHLAK\Config\Config;
-use PHPUnit\Framework\TestCase;
 use Psr\Http\Message\ResponseInterface;
 use Slim\Psr7\Response;
+use Tests\TestCase;
 
 class FileInfoControllerTest extends TestCase
 {
-    /** @var Config The application config */
-    protected $config;
-
-    public function setUp(): void
-    {
-        $this->config = new Config([
-            'app' => [
-                'max_hash_size' => 1000000000
-            ],
-        ]);
-    }
-
-    public function test_it_can_return_a_successful_response()
+    public function test_it_can_return_a_successful_response(): void
     {
         $controller = new FileInfoController($this->config);
 
@@ -32,7 +19,7 @@ class FileInfoControllerTest extends TestCase
         $this->assertEquals(200, $response->getStatusCode());
     }
 
-    public function test_it_can_return_a_not_found_response()
+    public function test_it_can_return_a_not_found_response(): void
     {
         $controller = new FileInfoController($this->config);
 
@@ -42,7 +29,7 @@ class FileInfoControllerTest extends TestCase
         $this->assertEquals(404, $response->getStatusCode());
     }
 
-    public function test_it_returns_an_error_when_file_size_is_too_large()
+    public function test_it_returns_an_error_when_file_size_is_too_large(): void
     {
         $this->config->set('app.max_hash_size', 10);
         $controller = new FileInfoController($this->config);
diff --git a/tests/Unit/Support/HelpersTest.php b/tests/Unit/Support/HelpersTest.php
index d395722..a3ae2ec 100644
--- a/tests/Unit/Support/HelpersTest.php
+++ b/tests/Unit/Support/HelpersTest.php
@@ -7,7 +7,7 @@ use PHPUnit\Framework\TestCase;
 
 class HelpersTest extends TestCase
 {
-    public function test_it_can_get_an_environment_variable()
+    public function test_it_can_get_an_environment_variable(): void
     {
         putenv('TEST_STRING=Test string; please ignore');
 
@@ -16,14 +16,14 @@ class HelpersTest extends TestCase
         $this->assertEquals('Test string; please ignore', $env);
     }
 
-    public function test_it_can_return_a_default_value()
+    public function test_it_can_return_a_default_value(): void
     {
         $env = Helpers::env('DEFAULT_TEST', 'Test default; please ignore');
 
         $this->assertEquals('Test default; please ignore', $env);
     }
 
-    public function test_it_can_a_retrieve_boolean_value()
+    public function test_it_can_a_retrieve_boolean_value(): void
     {
         putenv('TRUE_TEST=true');
         putenv('FALSE_TEST=false');
@@ -32,14 +32,14 @@ class HelpersTest extends TestCase
         $this->assertFalse(Helpers::env('FALSE_TEST'));
     }
 
-    public function test_it_can_retrieve_a_null_value()
+    public function test_it_can_retrieve_a_null_value(): void
     {
         putenv('NULL_TEST=null');
 
         $this->assertNull(Helpers::env('NULL_TEST'));
     }
 
-    public function test_it_can_be_surrounded_bys_quotation_marks()
+    public function test_it_can_be_surrounded_bys_quotation_marks(): void
     {
         putenv('QUOTES_TEST="Test charlie; please ignore"');