Merge remote-tracking branch 'MyIgel/mailing'

16 files changed, 881 insertions, 38 deletions

diff --git a/composer.json b/composer.json
index 622fbdfa..0632bbc3 100644
--- a/composer.json
+++ b/composer.json
@@ -29,6 +29,7 @@
         "psr/container": "^1.0",
         "psr/http-server-middleware": "^1.0",
         "psr/log": "^1.0",
+        "swiftmailer/swiftmailer": "^6.1",
         "symfony/http-foundation": "^3.3",
         "symfony/psr-http-message-bridge": "^1.0",
         "twig/extensions": "^1.5",
diff --git a/config/app.php b/config/app.php
index e309abe4..efe745e8 100644
--- a/config/app.php
+++ b/config/app.php
@@ -5,9 +5,13 @@
 return [
     // Service providers
     'providers'  => [
+
+        // Application bootstrap
         \Engelsystem\Logger\LoggerServiceProvider::class,
         \Engelsystem\Exceptions\ExceptionsServiceProvider::class,
         \Engelsystem\Config\ConfigServiceProvider::class,
+
+        // Request handling
         \Engelsystem\Http\UrlGeneratorServiceProvider::class,
         \Engelsystem\Renderer\RendererServiceProvider::class,
         \Engelsystem\Database\DatabaseServiceProvider::class,
@@ -19,13 +23,22 @@ return [
         \Engelsystem\Renderer\TwigServiceProvider::class,
         \Engelsystem\Middleware\RouteDispatcherServiceProvider::class,
         \Engelsystem\Middleware\RequestHandlerServiceProvider::class,
+
+        // Additional services
+        \Engelsystem\Mail\MailerServiceProvider::class,
     ],
 
     // Application middleware
     'middleware' => [
+
+        // Basic initialization
         \Engelsystem\Middleware\SendResponseHandler::class,
         \Engelsystem\Middleware\ExceptionHandler::class,
+
+        // Changes of request/response parameters
         \Engelsystem\Middleware\SetLocale::class,
+
+        // The application code
         \Engelsystem\Middleware\ErrorHandler::class,
         \Engelsystem\Middleware\RouteDispatcher::class,
         \Engelsystem\Middleware\RequestHandler::class,
diff --git a/config/config.default.php b/config/config.default.php
index dfccab0a..659a26b7 100644
--- a/config/config.default.php
+++ b/config/config.default.php
@@ -26,8 +26,24 @@ return [
     // Contact email address, linked on every page
     'contact_email'           => env('CONTACT_EMAIL', 'mailto:ticket@c3heaven.de'),
 
-    // From address of all emails
-    'no_reply_email'          => env('NO_REPLY_EMAIL', 'noreply@engelsystem.de'),
+    // Email config
+    'email'                   => [
+        // Can be mail, smtp, sendmail or log
+        'driver' => env('MAIL_DRIVER', 'smtp'),
+        'from'   => [
+            // From address of all emails
+            'address' => env('MAIL_FROM_ADDRESS', 'noreply@engelsystem.de'),
+            'name'    => env('MAIL_FROM_NAME', 'Engelsystem')
+        ],
+
+        'host'       => env('MAIL_HOST', 'localhost'),
+        'port'       => env('MAIL_PORT', 587),
+        // Transport encryption like tls
+        'encryption' => env('MAIL_ENCRYPTION', null),
+        'username'   => env('MAIL_USERNAME'),
+        'password'   => env('MAIL_PASSWORD'),
+        'sendmail'   => env('MAIL_SENDMAIL', '/usr/sbin/sendmail -bs'),
+    ],
 
     // Default theme, 1=style1.css
     'theme'                   => env('THEME', 1),
@@ -55,28 +71,27 @@ return [
     // Only arrived angels can sign up for shifts
     'signup_requires_arrival' => false,
 
-    // Anzahl Stunden bis zum Austragen eigener Schichten
+    // Number of hours that an angel has to sign out own shifts
     'last_unsubscribe'        => 3,
 
-    // Setzt den zu verwendenden Crypto-Algorithmus (entsprechend der Dokumentation von crypt()).
-    // Falls ein Benutzerpasswort in einem anderen Format gespeichert ist,
-    // wird es bei der ersten Benutzung des Klartext-Passworts in das neue Format
-    // konvertiert.
+    // Define the algorithm to use for `crypt()` of passwords
+    // If the user uses an old algorithm the password will be converted to the new format
     //  MD5         '$1'
     //  Blowfish    '$2y$13'
     //  SHA-256     '$5$rounds=5000'
     //  SHA-512     '$6$rounds=5000'
     'crypt_alg'               => '$6$rounds=5000',
 
+    // The minimum length for passwords
     'min_password_length'     => 8,
 
-    // Wenn Engel beim Registrieren oder in ihrem Profil eine T-Shirt Größe angeben sollen, auf true setzen:
+    // Enables the T-Shirt configuration on signup and profile
     'enable_tshirt_size'      => true,
 
     // Number of shifts to freeload until angel is locked for shift signup.
     'max_freeloadable_shifts' => 2,
 
-    // local timezone
+    // Local timezone
     'timezone'                => env('TIMEZONE', 'Europe/Berlin'),
 
     // Multiply 'night shifts' and freeloaded shifts (start or end between 2 and 6 exclusive) by 2
@@ -99,10 +114,11 @@ return [
         'en_US.UTF-8' => 'English',
     ],
 
-    'default_locale'  => env('DEFAULT_LOCALE', 'en_US.UTF-8'),
+    // The default locale to use
+    'default_locale'          => env('DEFAULT_LOCALE', 'en_US.UTF-8'),
 
     // Available T-Shirt sizes, set value to null if not available
-    'tshirt_sizes'    => [
+    'tshirt_sizes'            => [
         'S'    => 'S',
         'S-G'  => 'S Girl',
         'M'    => 'M',
@@ -117,5 +133,5 @@ return [
     ],
 
     // IP addresses of reverse proxies that are trusted, can be an array or a comma separated list
-    'trusted_proxies' => env('TRUSTED_PROXIES', ['127.0.0.0/8', '::ffff:127.0.0.0/8', '::1/128']),
+    'trusted_proxies'         => env('TRUSTED_PROXIES', ['127.0.0.0/8', '::ffff:127.0.0.0/8', '::1/128']),
 ];
diff --git a/includes/helper/email_helper.php b/includes/helper/email_helper.php
index a0631550..e9e5a323 100644
--- a/includes/helper/email_helper.php
+++ b/includes/helper/email_helper.php
@@ -1,5 +1,7 @@
 <?php
 
+use Engelsystem\Mail\EngelsystemMailer;
+
 /**
  * @param array  $recipient_user
  * @param string $title
@@ -18,38 +20,21 @@ function engelsystem_email_to_user($recipient_user, $title, $message, $not_if_it
     /** @var \Engelsystem\Helpers\Translator $translator */
     $translator = app()->get('translator');
     $locale = $translator->getLocale();
+    /** @var EngelsystemMailer $mailer */
+    $mailer = app('mailer');
 
     $translator->setLocale($recipient_user['Sprache']);
-    $message = sprintf(__('Hi %s,'), $recipient_user['Nick']) . "\n\n"
-        . __('here is a message for you from the engelsystem:') . "\n\n"
-        . $message . "\n\n"
-        . __('This email is autogenerated and has not been signed. You got this email because you are registered in the engelsystem.');
-    $translator->setLocale($locale);
-
-    return engelsystem_email($recipient_user['email'], $title, $message);
-}
-
-/**
- * @param string $address
- * @param string $title
- * @param string $message
- * @return bool
- */
-function engelsystem_email($address, $title, $message)
-{
-    $result = mail(
-        $address,
+    $status = $mailer->sendView(
+        $recipient_user['email'],
         $title,
-        $message,
-        sprintf(
-            "Content-Type: text/plain; charset=UTF-8\r\nFrom: Engelsystem <%s>",
-            config('no_reply_email')
-        )
+        'emails/mail',
+        ['user' => $recipient_user['Nick'], 'message' => $message]
     );
+    $translator->setLocale($locale);
 
-    if ($result === false) {
+    if (!$status) {
         engelsystem_error('Unable to send email.');
     }
 
-    return true;
+    return (bool)$status;
 }
diff --git a/src/Mail/EngelsystemMailer.php b/src/Mail/EngelsystemMailer.php
new file mode 100644
index 00000000..17047cc8
--- /dev/null
+++ b/src/Mail/EngelsystemMailer.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Engelsystem\Mail;
+
+use Engelsystem\Renderer\Renderer;
+use Swift_Mailer as SwiftMailer;
+
+class EngelsystemMailer extends Mailer
+{
+    /** @var Renderer|null */
+    protected $view;
+
+    public function __construct(SwiftMailer $mailer, Renderer $view = null)
+    {
+        parent::__construct($mailer);
+
+        $this->view = $view;
+    }
+
+    /**
+     * Send a template
+     *
+     * @param string $to
+     * @param string $subject
+     * @param string $template
+     * @param array  $data
+     * @return int
+     */
+    public function sendView($to, $subject, $template, $data = []): int
+    {
+        $body = $this->view->render($template, $data);
+
+        return $this->send($to, $subject, $body);
+    }
+}
diff --git a/src/Mail/Mailer.php b/src/Mail/Mailer.php
new file mode 100644
index 00000000..ed800986
--- /dev/null
+++ b/src/Mail/Mailer.php
@@ -0,0 +1,79 @@
+<?php
+
+namespace Engelsystem\Mail;
+
+use Engelsystem\Renderer\Renderer;
+use Swift_Mailer as SwiftMailer;
+use Swift_Message as SwiftMessage;
+
+class Mailer
+{
+    /** @var SwiftMailer */
+    protected $mailer;
+
+    /** @var Renderer|null */
+    protected $view;
+
+    /** @var string */
+    protected $fromAddress = '';
+
+    /** @var string */
+    protected $fromName = null;
+
+    public function __construct(SwiftMailer $mailer)
+    {
+        $this->mailer = $mailer;
+    }
+
+    /**
+     * Send the mail
+     *
+     * @param string|string[] $to
+     * @param string          $subject
+     * @param string          $body
+     * @return int
+     */
+    public function send($to, string $subject, string $body): int
+    {
+        /** @var SwiftMessage $message */
+        $message = $this->mailer->createMessage();
+        $message->setTo((array)$to)
+            ->setFrom($this->fromAddress, $this->fromName)
+            ->setSubject($subject)
+            ->setBody($body);
+
+        return $this->mailer->send($message);
+    }
+
+    /**
+     * @return string
+     */
+    public function getFromAddress(): string
+    {
+        return $this->fromAddress;
+    }
+
+    /**
+     * @param string $fromAddress
+     */
+    public function setFromAddress(string $fromAddress)
+    {
+        $this->fromAddress = $fromAddress;
+    }
+
+    /**
+     * @return string
+     */
+    public function getFromName(): string
+    {
+        return $this->fromName;
+    }
+
+    /**
+     * @param string $fromName
+     */
+    public function setFromName(string $fromName)
+    {
+        $this->fromName = $fromName;
+    }
+}
diff --git a/src/Mail/MailerServiceProvider.php b/src/Mail/MailerServiceProvider.php
new file mode 100644
index 00000000..989fee8f
--- /dev/null
+++ b/src/Mail/MailerServiceProvider.php
@@ -0,0 +1,89 @@
+<?php
+
+namespace Engelsystem\Mail;
+
+use Engelsystem\Config\Config;
+use Engelsystem\Container\ServiceProvider;
+use Engelsystem\Mail\Transport\LogTransport;
+use InvalidArgumentException;
+use Swift_Mailer as SwiftMailer;
+use Swift_SendmailTransport as SendmailTransport;
+use Swift_SmtpTransport as SmtpTransport;
+use Swift_Transport as Transport;
+
+class MailerServiceProvider extends ServiceProvider
+{
+    public function register()
+    {
+        /** @var Config $config */
+        $config = $this->app->get('config');
+        $mailConfig = $config->get('email');
+
+        $transport = $this->getTransport($mailConfig['driver'], $mailConfig);
+        $this->app->instance(Transport::class, $transport);
+        $this->app->instance('mailer.transport', $transport);
+
+        /** @var SwiftMailer $swiftMailer */
+        $swiftMailer = $this->app->make(SwiftMailer::class);
+        $this->app->instance(SwiftMailer::class, $swiftMailer);
+        $this->app->instance('mailer.swift', $swiftMailer);
+
+        /** @var Mailer $mailer */
+        $mailer = $this->app->make(EngelsystemMailer::class);
+        $mailer->setFromAddress($mailConfig['from']['address']);
+        if (!empty($mailConfig['from']['name'])) {
+            $mailer->setFromName($mailConfig['from']['name']);
+        }
+
+        $this->app->instance(EngelsystemMailer::class, $mailer);
+        $this->app->instance(Mailer::class, $mailer);
+        $this->app->instance('mailer', $mailer);
+    }
+
+    /**
+     * @param string $transport
+     * @param array  $config
+     * @return Transport
+     */
+    protected function getTransport($transport, $config)
+    {
+        switch ($transport) {
+            case 'log':
+                return $this->app->make(LogTransport::class);
+            case 'mail':
+            case 'sendmail':
+                return $this->app->make(SendmailTransport::class, ['command' => $config['sendmail']]);
+            case 'smtp':
+                return $this->getSmtpTransport($config);
+        }
+
+        throw new InvalidArgumentException(sprintf('Mail driver "%s" not found', $transport));
+    }
+
+    /**
+     * @param array $config
+     * @return SmtpTransport
+     */
+    protected function getSmtpTransport(array $config)
+    {
+        /** @var SmtpTransport $transport */
+        $transport = $this->app->make(SmtpTransport::class, [
+            'host'       => $config['host'],
+            'port'       => $config['port'],
+            'encryption' => $config['encryption'],
+            // TODO: The security variable should be removed in the future
+            // https://github.com/swiftmailer/swiftmailer/commit/d3d6a98ab7dc155a04eb08273db7cd34606e7b5e#commitcomment-30462876
+            'security'   => $config['encryption'],
+        ]);
+
+        if ($config['username']) {
+            $transport->setUsername($config['username']);
+        }
+
+        if ($config['password']) {
+            $transport->setPassword($config['password']);
+        }
+
+        return $transport;
+    }
+}
diff --git a/src/Mail/Transport/LogTransport.php b/src/Mail/Transport/LogTransport.php
new file mode 100644
index 00000000..6e351302
--- /dev/null
+++ b/src/Mail/Transport/LogTransport.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace Engelsystem\Mail\Transport;
+
+use Psr\Log\LoggerInterface;
+use Swift_Mime_SimpleMessage as SimpleMessage;
+
+class LogTransport extends Transport
+{
+    /** @var LoggerInterface */
+    protected $logger;
+
+    public function __construct(LoggerInterface $logger)
+    {
+        $this->logger = $logger;
+    }
+
+    /**
+     * Send the given Message.
+     *
+     * Recipient/sender data will be retrieved from the Message API.
+     * The return value is the number of recipients
+     *
+     * @param SimpleMessage $message
+     * @param string[]      $failedRecipients An array of failures by-reference
+     *
+     * @return int
+     */
+    public function send(
+        SimpleMessage $message,
+        &$failedRecipients = null
+    ): int {
+        $this->logger->debug(
+            'Mail: Send mail "{title}" to "{recipients}":' . PHP_EOL . '{content}',
+            [
+                'title'      => $message->getSubject(),
+                'recipients' => $this->getTo($message),
+                'content'    => (string)$message->getHeaders() . PHP_EOL . PHP_EOL . $message->toString(),
+            ]
+        );
+
+        return count($this->allRecipients($message));
+    }
+}
diff --git a/src/Mail/Transport/Transport.php b/src/Mail/Transport/Transport.php
new file mode 100644
index 00000000..691faf60
--- /dev/null
+++ b/src/Mail/Transport/Transport.php
@@ -0,0 +1,103 @@
+<?php
+
+namespace Engelsystem\Mail\Transport;
+
+use Swift_Events_EventListener;
+use Swift_Mime_SimpleMessage as SimpleMessage;
+use Swift_Transport as SwiftTransport;
+
+abstract class Transport implements SwiftTransport
+{
+    /**
+     * Test if this Transport mechanism has started.
+     *
+     * @return bool
+     */
+    public function isStarted(): bool
+    {
+        return true;
+    }
+
+    /**
+     * Start this Transport mechanism.
+     */
+    public function start() { }
+
+    /**
+     * Stop this Transport mechanism.
+     */
+    public function stop() { }
+
+    /**
+     * Check if this Transport mechanism is alive.
+     *
+     * If a Transport mechanism session is no longer functional, the method
+     * returns FALSE. It is the responsibility of the developer to handle this
+     * case and restart the Transport mechanism manually.
+     *
+     * @example
+     *
+     *   if (!$transport->ping()) {
+     *      $transport->stop();
+     *      $transport->start();
+     *   }
+     *
+     * The Transport mechanism will be started, if it is not already.
+     *
+     * It is undefined if the Transport mechanism attempts to restart as long as
+     * the return value reflects whether the mechanism is now functional.
+     *
+     * @return bool TRUE if the transport is alive
+     */
+    public function ping(): bool
+    {
+        return true;
+    }
+
+    /**
+     * Register a plugin in the Transport.
+     *
+     * @param Swift_Events_EventListener $plugin
+     */
+    public function registerPlugin(Swift_Events_EventListener $plugin) { }
+
+    /**
+     * Returns a unified list of all recipients
+     *
+     * @param SimpleMessage $message
+     * @return array
+     */
+    protected function allRecipients(SimpleMessage $message): array
+    {
+        return array_merge(
+            (array)$message->getTo(),
+            (array)$message->getCc(),
+            (array)$message->getBcc()
+        );
+    }
+
+    /**
+     * Returns a concatenated list of mail recipients
+     *
+     * @param  SimpleMessage $message
+     * @return string
+     */
+    protected function getTo(SimpleMessage $message): string
+    {
+        return $this->formatTo($this->allRecipients($message));
+    }
+
+    /**
+     * @param array $recipients
+     * @return string
+     */
+    protected function formatTo(array $recipients)
+    {
+        $list = [];
+        foreach ($recipients as $address => $name) {
+            $list[] = $name ? sprintf('%s <%s>', $name, $address) : $address;
+        }
+
+        return implode(',', $list);
+    }
+}
diff --git a/templates/emails/mail.twig b/templates/emails/mail.twig
new file mode 100644
index 00000000..f5ac5860
--- /dev/null
+++ b/templates/emails/mail.twig
@@ -0,0 +1,6 @@
+{{ __('Hi %s,', [user]) }}
+
+{{ __('here is a message for you from the engelsystem:') }}
+{{ message|raw }}
+
+{{ __('This email is autogenerated and has not been signed. You got this email because you are registered in the engelsystem.') }}
diff --git a/tests/Unit/Mail/EngelsystemMailerTest.php b/tests/Unit/Mail/EngelsystemMailerTest.php
new file mode 100644
index 00000000..aae6e267
--- /dev/null
+++ b/tests/Unit/Mail/EngelsystemMailerTest.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace Engelsystem\Test\Unit\Mail;
+
+use Engelsystem\Mail\EngelsystemMailer;
+use Engelsystem\Renderer\Renderer;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Swift_Mailer as SwiftMailer;
+
+class EngelsystemMailerTest extends TestCase
+{
+    /**
+     * @covers \Engelsystem\Mail\EngelsystemMailer::__construct
+     * @covers \Engelsystem\Mail\EngelsystemMailer::sendView
+     */
+    public function testSendView()
+    {
+        /** @var Renderer|MockObject $view */
+        $view = $this->createMock(Renderer::class);
+        /** @var SwiftMailer|MockObject $swiftMailer */
+        $swiftMailer = $this->createMock(SwiftMailer::class);
+        /** @var EngelsystemMailer|MockObject $mailer */
+        $mailer = $this->getMockBuilder(EngelsystemMailer::class)
+            ->setConstructorArgs(['mailer' => $swiftMailer, 'view' => $view])
+            ->setMethods(['send'])
+            ->getMock();
+        $mailer->expects($this->once())
+            ->method('send')
+            ->with('foo@bar.baz', 'Lorem dolor', 'Rendered Stuff!')
+            ->willReturn(1);
+        $view->expects($this->once())
+            ->method('render')
+            ->with('test/template.tpl', ['dev' => true])
+            ->willReturn('Rendered Stuff!');
+
+        $return = $mailer->sendView('foo@bar.baz', 'Lorem dolor', 'test/template.tpl', ['dev' => true]);
+        $this->equalTo(1, $return);
+    }
+}
diff --git a/tests/Unit/Mail/MailerServiceProviderTest.php b/tests/Unit/Mail/MailerServiceProviderTest.php
new file mode 100644
index 00000000..0c841e9e
--- /dev/null
+++ b/tests/Unit/Mail/MailerServiceProviderTest.php
@@ -0,0 +1,177 @@
+<?php
+
+namespace Engelsystem\Test\Unit\Middleware;
+
+use Engelsystem\Application;
+use Engelsystem\Config\Config;
+use Engelsystem\Mail\EngelsystemMailer;
+use Engelsystem\Mail\Mailer;
+use Engelsystem\Mail\MailerServiceProvider;
+use Engelsystem\Mail\Transport\LogTransport;
+use Engelsystem\Test\Unit\ServiceProviderTest;
+use InvalidArgumentException;
+use Psr\Log\LoggerInterface;
+use Swift_Mailer as SwiftMailer;
+use Swift_SendmailTransport as SendmailTransport;
+use Swift_SmtpTransport as SmtpTransport;
+use Swift_Transport as Transport;
+
+class MailerServiceProviderTest extends ServiceProviderTest
+{
+    /** @var array */
+    protected $defaultConfig = [
+        'email' => [
+            'driver'   => 'mail',
+            'from'     => [
+                'name'    => 'Engelsystem',
+                'address' => 'foo@bar.batz',
+            ],
+            'sendmail' => '/opt/bin/sendmail -bs',
+        ],
+    ];
+
+    /** @var array */
+    protected $smtpConfig = [
+        'email' => [
+            'driver'     => 'smtp',
+            'host'       => 'mail.foo.bar',
+            'port'       => 587,
+            'encryption' => 'tls',
+            'username'   => 'foobar',
+            'password'   => 'LoremIpsum123',
+        ],
+    ];
+
+    /**
+     * @covers \Engelsystem\Mail\MailerServiceProvider::register
+     */
+    public function testRegister()
+    {
+        $app = $this->getApplication();
+
+        $serviceProvider = new MailerServiceProvider($app);
+        $serviceProvider->register();
+
+        $this->assertExistsInContainer(['mailer.transport', Transport::class], $app);
+        $this->assertExistsInContainer(['mailer.swift', SwiftMailer::class], $app);
+        $this->assertExistsInContainer(['mailer', EngelsystemMailer::class, Mailer::class], $app);
+
+        /** @var EngelsystemMailer $mailer */
+        $mailer = $app->get('mailer');
+        $this->assertEquals('Engelsystem', $mailer->getFromName());
+        $this->assertEquals('foo@bar.batz', $mailer->getFromAddress());
+
+        /** @var SendmailTransport $transport */
+        $transport = $app->get('mailer.transport');
+        $this->assertEquals($this->defaultConfig['email']['sendmail'], $transport->getCommand());
+    }
+
+    /**
+     * @return array
+     */
+    public function provideTransports()
+    {
+        return [
+            [LogTransport::class, ['email' => ['driver' => 'log']]],
+            [SendmailTransport::class, ['email' => ['driver' => 'mail']]],
+            [SendmailTransport::class, ['email' => ['driver' => 'sendmail']]],
+            [
+                SmtpTransport::class,
+                $this->smtpConfig
+            ],
+        ];
+    }
+
+    /**
+     * @covers       \Engelsystem\Mail\MailerServiceProvider::getTransport
+     * @param string $class
+     * @param array  $emailConfig
+     * @dataProvider provideTransports
+     */
+    public function testGetTransport($class, $emailConfig = [])
+    {
+        $app = $this->getApplication($emailConfig);
+
+        $serviceProvider = new MailerServiceProvider($app);
+        $serviceProvider->register();
+
+        $transport = $app->get('mailer.transport');
+        $this->assertInstanceOf($class, $transport);
+    }
+
+    /**
+     * @covers \Engelsystem\Mail\MailerServiceProvider::getTransport
+     */
+    public function testGetTransportNotFound()
+    {
+        $app = $this->getApplication(['email' => ['driver' => 'foo-bar-batz']]);
+        $this->expectException(InvalidArgumentException::class);
+
+        $serviceProvider = new MailerServiceProvider($app);
+        $serviceProvider->register();
+    }
+
+    /**
+     * @covers \Engelsystem\Mail\MailerServiceProvider::getSmtpTransport
+     */
+    public function testGetSmtpTransport()
+    {
+        $app = $this->getApplication($this->smtpConfig);
+
+        $serviceProvider = new MailerServiceProvider($app);
+        $serviceProvider->register();
+
+        /** @var SmtpTransport $transport */
+        $transport = $app->get('mailer.transport');
+
+        $this->assertEquals($this->smtpConfig['email']['host'], $transport->getHost());
+        $this->assertEquals($this->smtpConfig['email']['port'], $transport->getPort());
+        $this->assertEquals($this->smtpConfig['email']['encryption'], $transport->getEncryption());
+        $this->assertEquals($this->smtpConfig['email']['username'], $transport->getUsername());
+        $this->assertEquals($this->smtpConfig['email']['password'], $transport->getPassword());
+    }
+
+    /**
+     * @param array $configuration
+     * @return Application
+     */
+    protected function getApplication($configuration = []): Application
+    {
+        $app = new Application();
+
+        $configuration = new Config(array_replace_recursive($this->defaultConfig, $configuration));
+        $app->instance('config', $configuration);
+
+        $logger = $this->getMockForAbstractClass(LoggerInterface::class);
+        $app->instance(LoggerInterface::class, $logger);
+
+        return $app;
+    }
+
+    /**
+     * @param string[]    $abstracts
+     * @param Application $container
+     */
+    protected function assertExistsInContainer($abstracts, $container)
+    {
+        $first = array_shift($abstracts);
+        $this->assertContainerHas($first, $container);
+
+        foreach ($abstracts as $abstract) {
+            $this->assertContainerHas($abstract, $container);
+            $this->assertEquals($container->get($first), $container->get($abstract));
+        }
+    }
+
+    /**
+     * @param string      $abstract
+     * @param Application $container
+     */
+    protected function assertContainerHas($abstract, $container)
+    {
+        $this->assertTrue(
+            $container->has($abstract) || $container->hasMethodBinding($abstract),
+            sprintf('Container does not contain abstract %s', $abstract)
+        );
+    }
+}
diff --git a/tests/Unit/Mail/MailerTest.php b/tests/Unit/Mail/MailerTest.php
new file mode 100644
index 00000000..24c6f69a
--- /dev/null
+++ b/tests/Unit/Mail/MailerTest.php
@@ -0,0 +1,77 @@
+<?php
+
+namespace Engelsystem\Test\Unit\Mail;
+
+use Engelsystem\Mail\Mailer;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Swift_Mailer as SwiftMailer;
+use Swift_Message as SwiftMessage;
+
+class MailerTest extends TestCase
+{
+    /**
+     * @covers \Engelsystem\Mail\Mailer::__construct
+     * @covers \Engelsystem\Mail\Mailer::getFromAddress
+     * @covers \Engelsystem\Mail\Mailer::setFromAddress
+     * @covers \Engelsystem\Mail\Mailer::getFromName
+     * @covers \Engelsystem\Mail\Mailer::setFromName
+     */
+    public function testInitAndSettersAndGetters()
+    {
+        /** @var SwiftMailer|MockObject $swiftMailer */
+        $swiftMailer = $this->createMock(SwiftMailer::class);
+
+        $mailer = new Mailer($swiftMailer);
+
+        $mailer->setFromName('From Name');
+        $this->assertEquals('From Name', $mailer->getFromName());
+
+        $mailer->setFromAddress('from@foo.bar');
+        $this->assertEquals('from@foo.bar', $mailer->getFromAddress());
+    }
+
+    /**
+     * @covers \Engelsystem\Mail\Mailer::send
+     */
+    public function testSend()
+    {
+        /** @var SwiftMessage|MockObject $message */
+        $message = $this->createMock(SwiftMessage::class);
+        /** @var SwiftMailer|MockObject $swiftMailer */
+        $swiftMailer = $this->createMock(SwiftMailer::class);
+        $swiftMailer->expects($this->once())
+            ->method('createMessage')
+            ->willReturn($message);
+        $swiftMailer->expects($this->once())
+            ->method('send')
+            ->willReturn(1);
+
+        $message->expects($this->once())
+            ->method('setTo')
+            ->with(['to@xam.pel'])
+            ->willReturn($message);
+
+        $message->expects($this->once())
+            ->method('setFrom')
+            ->with('foo@bar.baz', 'Lorem Ipsum')
+            ->willReturn($message);
+
+        $message->expects($this->once())
+            ->method('setSubject')
+            ->with('Foo Bar')
+            ->willReturn($message);
+
+        $message->expects($this->once())
+            ->method('setBody')
+            ->with('Lorem Ipsum!')
+            ->willReturn($message);
+
+        $mailer = new Mailer($swiftMailer);
+        $mailer->setFromAddress('foo@bar.baz');
+        $mailer->setFromName('Lorem Ipsum');
+
+        $return = $mailer->send('to@xam.pel', 'Foo Bar', 'Lorem Ipsum!');
+        $this->equalTo(1, $return);
+    }
+}
diff --git a/tests/Unit/Mail/Transport/LogTransportTest.php b/tests/Unit/Mail/Transport/LogTransportTest.php
new file mode 100644
index 00000000..5eb3a667
--- /dev/null
+++ b/tests/Unit/Mail/Transport/LogTransportTest.php
@@ -0,0 +1,60 @@
+<?php
+
+namespace Engelsystem\Test\Unit\Mail\Transport;
+
+use Engelsystem\Mail\Transport\LogTransport;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Psr\Log\LoggerInterface;
+use Swift_Mime_SimpleMessage as SimpleMessage;
+
+class LogTransportTest extends TestCase
+{
+    /**
+     * @covers \Engelsystem\Mail\Transport\LogTransport::__construct
+     * @covers \Engelsystem\Mail\Transport\LogTransport::send
+     */
+    public function testSend()
+    {
+        /** @var LoggerInterface|MockObject $logger */
+        $logger = $this->getMockForAbstractClass(LoggerInterface::class);
+        /** @var SimpleMessage|MockObject $message */
+        $message = $this->createMock(SimpleMessage::class);
+
+        $message->expects($this->once())
+            ->method('getSubject')
+            ->willReturn('Some subject');
+        $message->expects($this->once())
+            ->method('getHeaders')
+            ->willReturn('Head: er');
+        $message->expects($this->once())
+            ->method('toString')
+            ->willReturn('Message body');
+
+        $logger->expects($this->once())
+            ->method('debug')
+            ->willReturnCallback(function ($message, $context = []) {
+                foreach (array_keys($context) as $key) {
+                    $this->assertContains(sprintf('{%s}', $key), $message);
+                }
+
+                $this->assertEquals('Some subject', $context['title']);
+                $this->assertEquals('foo@bar.batz,Lorem Ipsum <lor@em.ips>', $context['recipients']);
+                $this->assertContains('Head: er', $context['content']);
+                $this->assertContains('Message body', $context['content']);
+            });
+
+        /** @var LogTransport|MockObject $transport */
+        $transport = $this->getMockBuilder(LogTransport::class)
+            ->setConstructorArgs(['logger' => $logger])
+            ->setMethods(['allRecipients'])
+            ->getMock();
+        $transport->expects($this->exactly(2))
+            ->method('allRecipients')
+            ->with($message)
+            ->willReturn(['foo@bar.batz' => null, 'lor@em.ips' => 'Lorem Ipsum']);
+
+        $return = $transport->send($message);
+        $this->equalTo(2, $return);
+    }
+}
diff --git a/tests/Unit/Mail/Transport/Stub/TransportImplementation.php b/tests/Unit/Mail/Transport/Stub/TransportImplementation.php
new file mode 100644
index 00000000..e3667c6e
--- /dev/null
+++ b/tests/Unit/Mail/Transport/Stub/TransportImplementation.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Engelsystem\Test\Unit\Mail\Transport\Stub;
+
+use Engelsystem\Mail\Transport\Transport;
+use Swift_Mime_SimpleMessage as SimpleMessage;
+
+class TransportImplementation extends Transport
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function send(SimpleMessage $message, &$failedRecipients = null)
+    {
+        return 0;
+    }
+
+    /**
+     * @param SimpleMessage $message
+     * @return array
+     */
+    public function getAllRecipients(SimpleMessage $message)
+    {
+        return $this->allRecipients($message);
+    }
+
+    /**
+     * @param SimpleMessage $message
+     * @return string
+     */
+    public function getGetTo(SimpleMessage $message)
+    {
+        return $this->getTo($message);
+    }
+}
diff --git a/tests/Unit/Mail/Transport/TransportTest.php b/tests/Unit/Mail/Transport/TransportTest.php
new file mode 100644
index 00000000..60f2079d
--- /dev/null
+++ b/tests/Unit/Mail/Transport/TransportTest.php
@@ -0,0 +1,83 @@
+<?php
+
+namespace Engelsystem\Test\Unit\Mail\Transport;
+
+use Engelsystem\Test\Unit\Mail\Transport\Stub\TransportImplementation;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Swift_Mime_SimpleMessage as SimpleMessage;
+
+class TransportTest extends TestCase
+{
+    /**
+     * @covers \Engelsystem\Mail\Transport\Transport::isStarted
+     * @covers \Engelsystem\Mail\Transport\Transport::ping
+     */
+    public function testMethods()
+    {
+        $transport = new TransportImplementation();
+
+        $this->assertTrue($transport->isStarted());
+        $this->assertTrue($transport->ping());
+    }
+
+    /**
+     * @covers \Engelsystem\Mail\Transport\Transport::allRecipients
+     */
+    public function testAllRecipients()
+    {
+        /** @var SimpleMessage|MockObject $message */
+        $message = $this->createMock(SimpleMessage::class);
+        $transport = new TransportImplementation();
+        $message->expects($this->once())
+            ->method('getTo')
+            ->willReturn([
+                'foo@bar.batz'      => 'Foo Bar',
+                'lorem@ipsum.dolor' => null,
+            ]);
+        $message->expects($this->once())
+            ->method('getCc')
+            ->willReturn([
+                'to@bar.batz' => null,
+            ]);
+        $message->expects($this->once())
+            ->method('getBcc')
+            ->willReturn([
+                'secret@bar.batz' => 'I\'m secret!',
+            ]);
+
+        $this->assertEquals(
+            [
+                'foo@bar.batz'      => 'Foo Bar',
+                'lorem@ipsum.dolor' => null,
+                'to@bar.batz'       => null,
+                'secret@bar.batz'   => 'I\'m secret!',
+            ],
+            $transport->getAllRecipients($message)
+        );
+    }
+
+    /**
+     * @covers \Engelsystem\Mail\Transport\Transport::getTo
+     * @covers \Engelsystem\Mail\Transport\Transport::formatTo
+     */
+    public function testGetTo()
+    {
+        /** @var SimpleMessage|MockObject $message */
+        $message = $this->createMock(SimpleMessage::class);
+        /** @var TransportImplementation|MockObject $transport */
+        $transport = $this->getMockBuilder(TransportImplementation::class)
+            ->setMethods(['allRecipients'])
+            ->getMock();
+        $transport->expects($this->once())
+            ->method('allRecipients')
+            ->with($message)
+            ->willReturn([
+                'foo@bar.batz'      => null,
+                'lorem@ipsum.dolor' => 'Developer',
+            ]);
+
+        $return = $transport->getGetTo($message);
+        $this->assertEquals('foo@bar.batz,Developer <lorem@ipsum.dolor>', $return);
+    }
+}