diff --git a/composer.json b/composer.json
index 327e025..883033b 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
     "name": "furyfire/backupscript",
-    "description": "Wrapper for Rclone based backup",
+    "description": "Wrapper for Rclone based backup with push notifications",
     "homepage": "https://jcktrue.dk",
     "version": "0.1.0",
     "require": {
diff --git a/composer.lock b/composer.lock
index 80304e4..7b96069 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "7c0718c0e4c6eabc3fec9cc0dbf816e2",
+    "content-hash": "545ed8a092dd0e7cb6c11837968dafc7",
     "packages": [
         {
             "name": "dflydev/dot-access-data",
diff --git a/src/App.php b/src/App.php
index 75655f7..0d463e2 100644
--- a/src/App.php
+++ b/src/App.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App;
 
 use Symfony\Component\Yaml\Yaml;
@@ -11,21 +13,17 @@ use League\Config\Configuration;
 use Nette\Schema\Expect;
 
 /**
- * Application class
- *
  * Mostly working as a register pattern for the logging and configuration.
- *
- * @author  Jens True <jens.chr.true@gmail.com>
- * @license https://opensource.org/licenses/gpl-license.php GNU Public License
- * @link    https://jcktrue.dk
  */
 class App
 {
+    /// Logging instance
     protected Logger $logger;
+    /// Configuration singleton
     protected Configuration $config;
 
     /**
-     * Create a new instance providing a config file
+     * Create a new instance providing a config file.
      *
      * @param string $configFile Relative or full path to YML config.
      * @SuppressWarnings(PHPMD.StaticAccess)
diff --git a/src/CommandBackup.php b/src/CommandBackup.php
index a663bc2..8504f34 100644
--- a/src/CommandBackup.php
+++ b/src/CommandBackup.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App;
 
 use Symfony\Component\Console\Attribute\AsCommand;
@@ -28,6 +30,18 @@ class CommandBackup extends Command
         );
     }
 
+    /**
+     * Start the backup process.
+     *
+     * 1. Read the configuration file.
+     * 2. For each configured backup entry
+     *    1. Get the size of the source
+     *    2. Get the size of the destination
+     *    3. Perform the backup
+     *    4. Get the new size of the destination
+     *    5. Send push notifications.
+     * 3. Report final success
+     */
     protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $sio = new SymfonyStyle($input, $output);
diff --git a/src/CommandShow.php b/src/CommandShow.php
index 0bcedc1..2c8b290 100644
--- a/src/CommandShow.php
+++ b/src/CommandShow.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App;
 
 use Symfony\Component\Console\Attribute\AsCommand;
diff --git a/src/Notification/Notification.php b/src/Notification/Notification.php
index b045690..1e9eaae 100644
--- a/src/Notification/Notification.php
+++ b/src/Notification/Notification.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Notification;
 
 use App\Notification\Ntfy;
diff --git a/src/Notification/NotificationInterface.php b/src/Notification/NotificationInterface.php
index 7180e71..9d2ef40 100644
--- a/src/Notification/NotificationInterface.php
+++ b/src/Notification/NotificationInterface.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Notification;
 
 interface NotificationInterface
diff --git a/src/Notification/Ntfy.php b/src/Notification/Ntfy.php
index ea71c0a..17b822b 100644
--- a/src/Notification/Ntfy.php
+++ b/src/Notification/Ntfy.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Notification;
 
 use Ntfy\Server;
diff --git a/src/Rclone/Rclone.php b/src/Rclone/Rclone.php
index 3847482..b2976f1 100644
--- a/src/Rclone/Rclone.php
+++ b/src/Rclone/Rclone.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Rclone;
 
 use Psr\Log\LoggerAwareTrait;
diff --git a/src/Template/Twig.php b/src/Template/Twig.php
index 0b199b9..63b1557 100644
--- a/src/Template/Twig.php
+++ b/src/Template/Twig.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Template;
 
 use Twig\Environment;
diff --git a/src/Template/TwigExtension.php b/src/Template/TwigExtension.php
index ef85b7a..44c1013 100644
--- a/src/Template/TwigExtension.php
+++ b/src/Template/TwigExtension.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace App\Template;
 
 use Symfony\Component\DependencyInjection\ContainerInterface;
diff --git a/tests/AppTest.php b/tests/AppTest.php
new file mode 100644
index 0000000..72a21f1
--- /dev/null
+++ b/tests/AppTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests;
+
+use PHPUnit\Framework\TestCase;
+use PHPUnit\Framework\Attributes\CoversClass;
+use Psr\Log\LoggerInterface;
+use App\App;
+
+#[CoversClass(App::class)]
+final class AppTest extends \PHPUnit\Framework\TestCase
+{
+    public function testNonexistentConfigFile(): void
+    {
+        $this->expectException(\Exception::class);
+        new App('no_file');
+        $this->fail('Exception was not thrown');
+    }
+
+    public function testGoodConfig(): void
+    {
+        $app = new App('config.example.yml');
+        $this->assertEquals('output.log', $app->getConfig('log'));
+        $this->assertInstanceOf(LoggerInterface::class, $app->getLogger());
+    }
+}
diff --git a/tests/Rclone/RcloneTest.php b/tests/Rclone/RcloneTest.php
index 4d7b25d..61be9df 100644
--- a/tests/Rclone/RcloneTest.php
+++ b/tests/Rclone/RcloneTest.php
@@ -23,15 +23,15 @@ final class RcloneTest extends TestCase
     public function testRclonePath(): void
     {
         $this->expectException(\Exception::class);
-        $rclone = new Rclone('invalid');
-        $this->assertEquals('', $rclone->getVersion());
+        new Rclone('invalid');
+        $this->fail('Exception was not thrown');
     }
 
     public function testRcloneInvalidVersion(): void
     {
         $this->expectException(\Exception::class);
-        $rclone = new Rclone('uname');
-        $this->assertEquals('', $rclone->getVersion());
+        new Rclone('uname');
+        $this->fail('Exception was not thrown');
     }
 
     public function testRcloneValidVersion(): void
@@ -49,7 +49,7 @@ final class RcloneTest extends TestCase
         $this->expectException(\Exception::class);
         $this->expectExceptionMessage("ERROR");
         $size = $rclone->getSize('temp/bogus-source');
-        $this->assertEquals(0, $size);
+        $this->fail('Exception was not thrown');
     }
 
     public function testRcloneCopy(): void
@@ -65,6 +65,6 @@ final class RcloneTest extends TestCase
         $this->expectException(\Exception::class);
         $this->expectExceptionMessage("ERROR");
         $rclone->copy('temp/bogus-source', 'temp/bogus-destination');
-        $this->assertDirectoryDoesNotExist('temp/bogus-destination');
+        $this->fail('Exception was not thrown');
     }
 }
diff --git a/tests/Template/TwigExtensionTest.php b/tests/Template/TwigExtensionTest.php
new file mode 100644
index 0000000..92e5438
--- /dev/null
+++ b/tests/Template/TwigExtensionTest.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests;
+
+use PHPUnit\Framework\TestCase;
+use PHPUnit\Framework\Attributes\DataProvider;
+use App\Template\TwigExtension;
+use Twig\TwigFilter;
+
+final class TwigExtensionTest extends \PHPUnit\Framework\TestCase
+{
+    public function testGetFilters(): void
+    {
+        $obj = new TwigExtension();
+        $filters = $obj->getFilters();
+        $this->assertContainsOnlyInstancesOf(TwigFilter::class, $filters);
+    }
+
+
+    public function testformatBytes(): void
+    {
+        $obj = new TwigExtension();
+        $this->assertEquals('1.00B', $obj->formatBytes(1, 2));
+        $this->assertEquals('2.00B', $obj->formatBytes(2, 2));
+        $this->assertEquals('10.00B', $obj->formatBytes(10, 2));
+        $this->assertEquals('0.98kB', $obj->formatBytes(1000, 2));
+        $this->assertEquals('1.00kB', $obj->formatBytes(1024, 2));
+        $this->assertEquals('512.00MB', $obj->formatBytes(1024 ** 3 / 2, 2));
+        $this->assertEquals('1.00GB', $obj->formatBytes(1024 ** 3 - 1, 2));
+        $this->assertEquals('1.00GB', $obj->formatBytes(1024 ** 3, 2));
+        $this->assertEquals('512.00GB', $obj->formatBytes(1024 ** 4 / 2, 2));
+        $this->assertEquals('1.00TB', $obj->formatBytes(1024 ** 4, 2));
+    }
+}