Extracted exception handler registration to a dedicated class

app/src/Bootstrap/AppManager.php

@@ -2,13 +2,13 @@
 
 namespace App\Bootstrap;
 
+use App\Exceptions\ExceptionManager;
 use App\Middlewares;
 use App\Providers;
 use DI\Bridge\Slim\Bridge;
 use DI\Container;
 use Invoker\CallableResolver;
 use Middlewares as HttpMiddlewares;
-use PHLAK\Config\Config;
 use Slim\App;
 use Tightenco\Collect\Support\Collection;
 
@@ -56,14 +56,7 @@ class AppManager
         $app = Bridge::create($this->container);
         $this->registerMiddlewares($app);
 
-        $this->container->call(function (App $app, Config $config): void {
-            if (! $config->get('app.debug', false)) {
-                return;
-            }
-
-            $errorMiddleware = $app->addErrorMiddleware(true, true, true);
-            $errorMiddleware->setDefaultErrorHandler(ErrorHandler::class);
-        });
+        $this->container->call(ExceptionManager::class);
 
         return $app;
     }

app/src/Exceptions/ErrorHandler.php

@@ -1,6 +1,6 @@
 <?php
 
-namespace App\Bootstrap;
+namespace App\Exceptions;
 
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;

app/src/Exceptions/ExceptionManager.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace App\Exceptions;
+
+use PHLAK\Config\Config;
+use Slim\App;
+
+class ExceptionManager
+{
+    /** @var App The application */
+    protected $app;
+
+    /** @var Config The application config */
+    protected $config;
+
+    /**
+     * Create a new ExceptionManager object.
+     *
+     * @param \Slim\App            $app
+     * @param \PHLAK\Config\Config $config
+     */
+    public function __construct(App $app, Config $config)
+    {
+        $this->app = $app;
+        $this->config = $config;
+    }
+
+    /**
+     * Set up and configure exception handling.
+     *
+     * @return void
+     */
+    public function __invoke(): void
+    {
+        if ($this->config->get('app.debug', false)) {
+            return;
+        }
+
+        $errorMiddleware = $this->app->addErrorMiddleware(true, true, true);
+        $errorMiddleware->setDefaultErrorHandler(ErrorHandler::class);
+    }
+}

tests/Exceptions/ErrorHandlerTest.php

@@ -2,7 +2,7 @@
 
 namespace Tests\Bootstrap;
 
-use App\Bootstrap\ErrorHandler;
+use App\Exceptions\ErrorHandler;
 use App\Providers\TwigProvider;
 use Exception;
 use Slim\Psr7\Request;

tests/Exceptions/ExceptionManagerTest.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace Tests\Exceptions;
+
+use App\Exceptions\ErrorHandler;
+use App\Exceptions\ExceptionManager;
+use Slim\App;
+use Slim\Middleware\ErrorMiddleware;
+use Tests\TestCase;
+
+class ExceptionManagerTest extends TestCase
+{
+    public function test_it_sets_the_default_error_handler(): void
+    {
+        $errorMiddleware = $this->createMock(ErrorMiddleware::class);
+        $errorMiddleware->expects($this->once())
+            ->method('setDefaultErrorHandler')
+            ->with(ErrorHandler::class);
+
+        $app = $this->createMock(App::class);
+        $app->expects($this->once())
+            ->method('addErrorMiddleware')
+            ->willReturn($errorMiddleware);
+
+        (new ExceptionManager($app, $this->config))();
+    }
+
+    public function test_it_does_not_set_the_default_error_handler_when_debug_is_enabled(): void
+    {
+        $this->config->set('app.debug', true);
+
+        $app = $this->createMock(App::class);
+        $app->expects($this->never())->method('addErrorMiddleware');
+
+        (new ExceptionManager($app, $this->config))();
+    }
+}