Merge pull request #347 from MyIgel/master

Implemented Container, closes #342

39 files changed, 1154 insertions, 178 deletions

diff --git a/.gitignore b/.gitignore
index d712148b..eb12eae7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,12 +14,14 @@ Thumbs.db
 _vimrc_local.vim
 .sass-cache
 
-# PHPstorm config
+# PHPstorm files
 /.idea/
+/.phpstorm.meta.php
 
 # Project files
 /config/config.php
 /test/coverage
+/public/coverage
 
 # Composer files
 /vendor/
diff --git a/composer.json b/composer.json
index 45dce626..35956e20 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,9 @@
         "php": ">=7.0.0",
         "erusev/parsedown": "1.6.*",
         "twbs/bootstrap": "^3.3",
-        "symfony/http-foundation": "^3.3"
+        "symfony/http-foundation": "^3.3",
+        "psr/container": "^1.0",
+        "psr/log": "^1.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^6.3"
diff --git a/config/config.default.php b/config/config.default.php
index 419b02d1..c2d742ef 100644
--- a/config/config.default.php
+++ b/config/config.default.php
@@ -44,6 +44,9 @@ return [
     // Number of News shown on one site
     'display_news'            => 6,
 
+    // Users are able to sign up
+    'registration_enabled'    => true,
+
     // Only arrived angels can sign up for shifts
     'signup_requires_arrival' => false,
 
diff --git a/db/update.sql b/db/update.sql
index 5d93e230..3ed37ceb 100644
--- a/db/update.sql
+++ b/db/update.sql
@@ -28,3 +28,6 @@ UPDATE `Groups` SET UID = UID * 10;
 INSERT INTO `Groups` (Name, UID) VALUES ('News Admin', -65);
 INSERT INTO `Privileges` (id, name, `desc`) VALUES (42, 'admin_news_html', 'Use HTML in news');
 INSERT INTO `GroupPrivileges` (group_id, privilege_id) VALUES (-65, 14), (-65, 42);
+
+-- Add log level to LogEntries
+ALTER TABLE `LogEntries` CHANGE COLUMN `nick` `level` VARCHAR(20) NOT NULL;
diff --git a/includes/engelsystem_provider.php b/includes/engelsystem_provider.php
index aed331d4..0de5e0f5 100644
--- a/includes/engelsystem_provider.php
+++ b/includes/engelsystem_provider.php
@@ -1,24 +1,36 @@
 <?php
 
+use Engelsystem\Application;
 use Engelsystem\Config\Config;
 use Engelsystem\Database\Db;
 use Engelsystem\Exceptions\Handler as ExceptionHandler;
 use Engelsystem\Http\Request;
+use Engelsystem\Logger\EngelsystemLogger;
 use Engelsystem\Renderer\HtmlEngine;
 use Engelsystem\Renderer\Renderer;
+use Engelsystem\Routing\UrlGenerator;
+use Psr\Log\LoggerInterface;
 use Symfony\Component\HttpFoundation\Session\Session;
+use Symfony\Component\HttpFoundation\Session\Storage\MockArraySessionStorage;
+use Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage;
 
 /**
  * This file includes all needed functions, connects to the db etc.
  */
-
 require_once __DIR__ . '/autoload.php';
 
+
+/**
+ * Initialize the application
+ */
+$app = Application::getInstance();
+
+
 /**
  * Load configuration
  */
 $config = new Config();
-Config::setInstance($config);
+$app->instance('config', $config);
 $config->set(require __DIR__ . '/../config/config.default.php');
 
 if (file_exists(__DIR__ . '/../config/config.php')) {
@@ -37,7 +49,8 @@ date_default_timezone_set($config->get('timezone'));
  * @var Request $request
  */
 $request = Request::createFromGlobals();
-$request::setInstance($request);
+$app->instance('request', $request);
+
 
 /**
  * Check for maintenance
@@ -49,17 +62,25 @@ if ($config->get('maintenance')) {
 
 
 /**
+ * Register UrlGenerator
+ */
+$urlGenerator = new UrlGenerator();
+$app->instance('routing.urlGenerator', $urlGenerator);
+
+
+/**
  * Initialize renderer
  */
 $renderer = new Renderer();
+$app->instance('renderer', $renderer);
 $renderer->addRenderer(new HtmlEngine());
-Renderer::setInstance($renderer);
 
 
 /**
  * Register error handler
  */
 $errorHandler = new ExceptionHandler();
+$app->instance('error.handler', $errorHandler);
 if (config('environment') == 'development') {
     $errorHandler->setEnvironment(ExceptionHandler::ENV_DEVELOPMENT);
     ini_set('display_errors', true);
@@ -80,6 +101,14 @@ Db::connect(
 Db::getPdo()->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 Db::getPdo()->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
 
+/**
+ * Init logger
+ */
+$logger = new EngelsystemLogger();
+$app->instance('logger', $logger);
+$app->instance(LoggerInterface::class, $logger);
+$app->instance(EngelsystemLogger::class, $logger);
+
 
 /**
  * Include legacy code
@@ -170,7 +199,9 @@ foreach ($includeFiles as $file) {
 /**
  * Init application
  */
-$session = new Session();
+$sessionStorage = (PHP_SAPI != 'cli' ? new NativeSessionStorage(['cookie_httponly' => true]) : new MockArraySessionStorage());
+$session = new Session($sessionStorage);
+$app->instance('session', $session);
 $session->start();
 $request->setSession($session);
 
diff --git a/includes/helper/internationalization_helper.php b/includes/helper/internationalization_helper.php
index 131941e9..efbe5db5 100644
--- a/includes/helper/internationalization_helper.php
+++ b/includes/helper/internationalization_helper.php
@@ -1,7 +1,5 @@
 <?php
 
-use Engelsystem\Http\Request;
-
 /**
  * Return currently active locale
  *
@@ -65,7 +63,7 @@ function gettext_locale($locale = null)
  */
 function make_langselect()
 {
-    $request = Request::getInstance();
+    $request = app('request');
 
     $items = [];
     foreach (config('locales') as $locale => $name) {
diff --git a/includes/model/LogEntries_model.php b/includes/model/LogEntries_model.php
index 0e11bf8e..f0ee6673 100644
--- a/includes/model/LogEntries_model.php
+++ b/includes/model/LogEntries_model.php
@@ -5,16 +5,16 @@ use Engelsystem\Database\DB;
 /**
  * Creates a log entry.
  *
- * @param string $nick    Username
- * @param string $message Log  Message
+ * @param string $logLevel Log level
+ * @param string $message  Log  Message
  * @return bool
  */
-function LogEntry_create($nick, $message)
+function LogEntry_create($logLevel, $message)
 {
     return DB::insert('
-        INSERT INTO `LogEntries` (`timestamp`, `nick`, `message`)
+        INSERT INTO `LogEntries` (`timestamp`, `level`, `message`)
         VALUES(?, ?, ?)
-    ', [time(), $nick, $message]);
+    ', [time(), $logLevel, $message]);
 }
 
 /**
@@ -43,7 +43,7 @@ function LogEntries_filter($keyword)
     return DB::select('
             SELECT *
             FROM `LogEntries`
-            WHERE `nick` LIKE ?
+            WHERE `level` LIKE ?
             OR `message` LIKE ?
             ORDER BY `timestamp` DESC
         ',
diff --git a/includes/pages/admin_log.php b/includes/pages/admin_log.php
index 03c9abb0..694b1d5a 100644
--- a/includes/pages/admin_log.php
+++ b/includes/pages/admin_log.php
@@ -17,12 +17,10 @@ function admin_log()
     if (request()->has('keyword')) {
         $filter = strip_request_item('keyword');
     }
-    $log_entries_source = LogEntries_filter($filter);
+    $log_entries = LogEntries_filter($filter);
 
-    $log_entries = [];
-    foreach ($log_entries_source as $log_entry) {
+    foreach ($log_entries as &$log_entry) {
         $log_entry['date'] = date('d.m.Y H:i', $log_entry['timestamp']);
-        $log_entries[] = $log_entry;
     }
 
     return page_with_title(admin_log_title(), [
@@ -33,7 +31,7 @@ function admin_log()
         ]),
         table([
             'date'    => 'Time',
-            'nick'    => 'Angel',
+            'level'   => 'Type',
             'message' => 'Log Entry'
         ], $log_entries)
     ]);
diff --git a/includes/pages/guest_login.php b/includes/pages/guest_login.php
index 9179c6c4..0577951f 100644
--- a/includes/pages/guest_login.php
+++ b/includes/pages/guest_login.php
@@ -33,7 +33,7 @@ function logout_title()
  */
 function guest_register()
 {
-    global $user;
+    global $user, $privileges;
     $tshirt_sizes = config('tshirt_sizes');
     $enable_tshirt_size = config('enable_tshirt_size');
     $min_password_length = config('min_password_length');
@@ -75,6 +75,14 @@ function guest_register()
         }
     }
 
+    if (!in_array('register', $privileges) || (!isset($user) && !config('registration_enabled'))) {
+        error(_('Registration is disabled.'));
+
+        return page_with_title(register_title(), [
+            msg(),
+        ]);
+    }
+
     if ($request->has('submit')) {
         $valid = true;
 
@@ -496,7 +504,7 @@ function get_register_hint()
 {
     global $privileges;
 
-    if (in_array('register', $privileges)) {
+    if (in_array('register', $privileges) && config('registration_enabled')) {
         return join('', [
             '<p>' . _('Please sign up, if you want to help us!') . '</p>',
             buttons([
diff --git a/includes/pages/user_atom.php b/includes/pages/user_atom.php
index 2991bdbf..c9d9398e 100644
--- a/includes/pages/user_atom.php
+++ b/includes/pages/user_atom.php
@@ -1,7 +1,6 @@
 <?php
 
 use Engelsystem\Database\DB;
-use Engelsystem\Http\Request;
 
 /**
  * Publically available page to feed the news to feed readers
@@ -45,7 +44,7 @@ function user_atom()
  */
 function make_atom_entries_from_news($news_entries)
 {
-    $request = Request::getInstance();
+    $request = app('request');
     $html = '<?xml version="1.0" encoding="utf-8"?>
   <feed xmlns="http://www.w3.org/2005/Atom">
   <title>Engelsystem</title>
diff --git a/includes/sys_log.php b/includes/sys_log.php
index c4ef890e..513586e6 100644
--- a/includes/sys_log.php
+++ b/includes/sys_log.php
@@ -9,10 +9,12 @@
 function engelsystem_log($message)
 {
     global $user;
-
     $nick = "Guest";
+    $logger = app('logger');
+
     if (isset($user)) {
         $nick = User_Nick_render($user);
     }
-    LogEntry_create($nick, $message);
+
+    $logger->info('{nick}: {message}', ['nick' => $nick, 'message' => $message]);
 }
diff --git a/includes/sys_menu.php b/includes/sys_menu.php
index 2eaa1234..385a6948 100644
--- a/includes/sys_menu.php
+++ b/includes/sys_menu.php
@@ -59,7 +59,7 @@ function header_toolbar()
         );
     }
 
-    if (!isset($user) && in_array('register', $privileges)) {
+    if (!isset($user) && in_array('register', $privileges) && config('registration_enabled')) {
         $toolbar_items[] = toolbar_item_link(page_link_to('register'), 'plus', register_title(), $page == 'register');
     }
 
diff --git a/includes/view/AngelTypes_view.php b/includes/view/AngelTypes_view.php
index f75cc616..baf0e04a 100644
--- a/includes/view/AngelTypes_view.php
+++ b/includes/view/AngelTypes_view.php
@@ -475,13 +475,27 @@ function AngelTypes_about_view_angeltype($angeltype)
  */
 function AngelTypes_about_view($angeltypes, $user_logged_in)
 {
+    global $privileges;
+
+    $buttons = [];
+
+    if ($user_logged_in) {
+        $buttons[] = button(page_link_to('angeltypes'), angeltypes_title(), 'back');
+    } else {
+        if (in_array('register', $privileges) && config('registration_enabled')) {
+            $buttons[] = button(page_link_to('register'), register_title());
+        }
+
+        $buttons[] = button(page_link_to('login'), login_title());
+    }
+
+    $faqUrl = config('faq_url');
+    if (!empty($faqUrl)) {
+        $buttons[] = button($faqUrl, _('FAQ'), 'btn-primary');
+    }
+
     $content = [
-        buttons([
-            !$user_logged_in ? button(page_link_to('register'), register_title()) : '',
-            !$user_logged_in ? button(page_link_to('login'), login_title()) : '',
-            $user_logged_in ? button(page_link_to('angeltypes'), angeltypes_title(), 'back') : '',
-            button(config('faq_url'), _('FAQ'), 'btn-primary')
-        ]),
+        buttons($buttons),
         '<p>' . _('Here is the list of teams and their tasks. If you have questions, read the FAQ.') . '</p>',
         '<hr />'
     ];
diff --git a/phpunit.xml b/phpunit.xml
index ff6eb120..bdc4b0b6 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,17 +1,19 @@
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         bootstrap="./includes/engelsystem_provider.php"
+         bootstrap="./includes/autoload.php"
          xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/6.3/phpunit.xsd"
          colors="true"
 >
     <testsuites>
-        <testsuite name="Models">
-            <directory>./test/model/</directory>
+        <testsuite name="Feature">
+            <directory>./tests/Feature</directory>
+        </testsuite>
+        <testsuite name="Unit">
+            <directory>./tests/Unit</directory>
         </testsuite>
     </testsuites>
     <filter>
         <whitelist>
             <directory>./include/</directory>
-            <directory>./public/</directory>
             <directory>./src/</directory>
         </whitelist>
     </filter>
diff --git a/public/.htaccess b/public/.htaccess
index c9d40187..2b1d3a7a 100644
--- a/public/.htaccess
+++ b/public/.htaccess
@@ -1,3 +1,4 @@
+
 <IfModule mod_rewrite.c>
     RewriteEngine on
 
diff --git a/public/index.php b/public/index.php
index b44e1491..c65dbdf8 100644
--- a/public/index.php
+++ b/public/index.php
@@ -1,7 +1,5 @@
 <?php
 
-use Engelsystem\Http\Request;
-
 require_once realpath(__DIR__ . '/../includes/engelsystem_provider.php');
 
 $free_pages = [
@@ -27,7 +25,6 @@ $page = '';
 $title = '';
 $content = '';
 
-/** @var Request $request */
 $page = $request->query->get('p');
 if (empty($page)) {
     $page = $request->path();
diff --git a/src/Application.php b/src/Application.php
new file mode 100644
index 00000000..674b3869
--- /dev/null
+++ b/src/Application.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Engelsystem;
+
+use Engelsystem\Container\Container;
+use Psr\Container\ContainerInterface;
+
+class Application extends Container
+{
+    public function __construct()
+    {
+        $this->registerBaseBindings();
+    }
+
+    protected function registerBaseBindings()
+    {
+        self::setInstance($this);
+        Container::setInstance($this);
+        $this->instance('app', $this);
+        $this->instance('container', $this);
+        $this->instance(Container::class, $this);
+        $this->instance(Application::class, $this);
+        $this->instance(ContainerInterface::class, $this);
+    }
+}
diff --git a/src/Config/Config.php b/src/Config/Config.php
index 02080de4..34c21a78 100644
--- a/src/Config/Config.php
+++ b/src/Config/Config.php
@@ -2,16 +2,9 @@
 
 namespace Engelsystem\Config;
 
-use ErrorException;
-
 class Config
 {
     /**
-     * @var self
-     */
-    protected static $instance;
-
-    /**
      * The config values
      *
      * @var array
@@ -104,25 +97,4 @@ class Config
     {
         $this->remove($key);
     }
-
-    /**
-     * @return Config
-     * @throws ErrorException
-     */
-    public static function getInstance()
-    {
-        if (!self::$instance instanceof self) {
-            throw new ErrorException('Config not initialized');
-        }
-
-        return self::$instance;
-    }
-
-    /**
-     * @param self $instance
-     */
-    public static function setInstance($instance)
-    {
-        self::$instance = $instance;
-    }
 }
diff --git a/src/Container/Container.php b/src/Container/Container.php
new file mode 100644
index 00000000..59a17a04
--- /dev/null
+++ b/src/Container/Container.php
@@ -0,0 +1,116 @@
+<?php
+
+namespace Engelsystem\Container;
+
+use Psr\Container\ContainerExceptionInterface;
+use Psr\Container\ContainerInterface;
+use Psr\Container\NotFoundExceptionInterface;
+
+class Container implements ContainerInterface
+{
+    /**
+     * The globally available container
+     *
+     * @var static
+     */
+    protected static $instance;
+
+    /**
+     * Contains the shared instances
+     *
+     * @var mixed[]
+     */
+    protected $instances = [];
+
+    /**
+     * Finds an entry of the container by its identifier and returns it
+     *
+     * @param string $id Identifier of the entry to look for
+     *
+     * @throws NotFoundExceptionInterface  No entry was found for **this** identifier
+     * @throws ContainerExceptionInterface Error while retrieving the entry
+     *
+     * @return mixed Entry
+     */
+    public function get($id)
+    {
+        if ($this->has($id)) {
+            return $this->resolve($id);
+        }
+
+        throw new NotFoundException(sprintf('The entry with the id "%s" could not be found', $id));
+    }
+
+    /**
+     * Register a shared entry in the container
+     *
+     * @param string $abstract Identifier of the entry to set
+     * @param mixed  $instance Entry
+     */
+    public function instance($abstract, $instance)
+    {
+        $this->singleton($abstract, $instance);
+    }
+
+    /**
+     * Register a shared entry as singleton in the container
+     *
+     * @param string $abstract
+     * @param mixed  $instance
+     */
+    public function singleton($abstract, $instance)
+    {
+        $this->instances[$abstract] = $instance;
+    }
+
+    /**
+     * Returns true if the container can return an entry for the given identifier
+     * Returns false otherwise
+     *
+     * `has($id)` returning true does not mean that `get($id)` will not throw an exception
+     * It does however mean that `get($id)` will not throw a `NotFoundExceptionInterface`
+     *
+     * @param string $id Identifier of the entry to look for
+     *
+     * @return bool
+     */
+    public function has($id)
+    {
+        return isset($this->instances[$id]);
+    }
+
+    /**
+     * Resolve the requested object
+     *
+     * @param string $abstract
+     * @return mixed
+     */
+    protected function resolve($abstract)
+    {
+        return $this->instances[$abstract];
+    }
+
+    /**
+     * Get the globally available instance of the container
+     *
+     * @return self
+     */
+    public static function getInstance()
+    {
+        if (is_null(static::$instance)) {
+            static::$instance = new static;
+        }
+
+        return static::$instance;
+    }
+
+    /**
+     * Set the globally available instance of the container
+     *
+     * @param Container $container
+     */
+    public static function setInstance(Container $container)
+    {
+        static::$instance = $container;
+    }
+}
diff --git a/src/Container/ContainerException.php b/src/Container/ContainerException.php
new file mode 100644
index 00000000..3cdde506
--- /dev/null
+++ b/src/Container/ContainerException.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Engelsystem\Container;
+
+use Exception;
+use Psr\Container\ContainerExceptionInterface;
+
+class ContainerException extends Exception implements ContainerExceptionInterface
+{
+
+}
diff --git a/src/Container/NotFoundException.php b/src/Container/NotFoundException.php
new file mode 100644
index 00000000..a83be0b1
--- /dev/null
+++ b/src/Container/NotFoundException.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace Engelsystem\Container;
+
+use Psr\Container\NotFoundExceptionInterface;
+
+class NotFoundException extends ContainerException implements NotFoundExceptionInterface
+{
+
+}
diff --git a/src/Exceptions/Handler.php b/src/Exceptions/Handler.php
index c4fb639c..95bcd132 100644
--- a/src/Exceptions/Handler.php
+++ b/src/Exceptions/Handler.php
@@ -42,7 +42,7 @@ class Handler
     /**
      * @param Throwable $e
      */
-    public function exceptionHandler(Throwable $e)
+    public function exceptionHandler($e)
     {
         $this->handle(
             'exception',
diff --git a/src/Http/Request.php b/src/Http/Request.php
index f0235d45..e7850c8b 100644
--- a/src/Http/Request.php
+++ b/src/Http/Request.php
@@ -2,14 +2,10 @@
 
 namespace Engelsystem\Http;
 
-use ErrorException;
 use Symfony\Component\HttpFoundation\Request as SymfonyRequest;
 
 class Request extends SymfonyRequest
 {
-    /** @var self */
-    protected static $instance;
-
     /**
      * Get POST input
      *
@@ -68,25 +64,4 @@ class Request extends SymfonyRequest
     {
         return rtrim(preg_replace('/\?.*/', '', $this->getUri()), '/');
     }
-
-    /**
-     * @return self
-     * @throws ErrorException
-     */
-    public static function getInstance()
-    {
-        if (!self::$instance instanceof self) {
-            throw new ErrorException('Request not initialized');
-        }
-
-        return self::$instance;
-    }
-
-    /**
-     * @param self $instance
-     */
-    public static function setInstance($instance)
-    {
-        self::$instance = $instance;
-    }
 }
diff --git a/src/Logger/EngelsystemLogger.php b/src/Logger/EngelsystemLogger.php
new file mode 100644
index 00000000..1f255b69
--- /dev/null
+++ b/src/Logger/EngelsystemLogger.php
@@ -0,0 +1,74 @@
+<?php
+
+namespace Engelsystem\Logger;
+
+use Psr\Log\AbstractLogger;
+use Psr\Log\InvalidArgumentException;
+use Psr\Log\LogLevel;
+
+class EngelsystemLogger extends AbstractLogger
+{
+    protected $allowedLevels = [
+        LogLevel::ALERT,
+        LogLevel::CRITICAL,
+        LogLevel::DEBUG,
+        LogLevel::EMERGENCY,
+        LogLevel::ERROR,
+        LogLevel::INFO,
+        LogLevel::NOTICE,
+        LogLevel::WARNING,
+    ];
+
+    /**
+     * Logs with an arbitrary level.
+     *
+     * @TODO: Implement $context['exception']
+     *
+     * @param mixed  $level
+     * @param string $message
+     * @param array  $context
+     *
+     * @throws InvalidArgumentException
+     */
+    public function log($level, $message, array $context = [])
+    {
+        if (!$this->checkLevel($level)) {
+            throw new InvalidArgumentException();
+        }
+
+        $message = $this->interpolate($message, $context);
+
+        LogEntry_create($level, $message);
+    }
+
+    /**
+     * Interpolates context values into the message placeholders.
+     *
+     * @param string $message
+     * @param array  $context
+     * @return string
+     */
+    protected function interpolate($message, array $context = [])
+    {
+        foreach ($context as $key => $val) {
+            // check that the value can be casted to string
+            if (is_array($val) || (is_object($val) && !method_exists($val, '__toString'))) {
+                continue;
+            }
+
+            // replace the values of the message
+            $message = str_replace('{' . $key . '}', $val, $message);
+        }
+
+        return $message;
+    }
+
+    /**
+     * @param string $level
+     * @return bool
+     */
+    protected function checkLevel($level)
+    {
+        return in_array($level, $this->allowedLevels);
+    }
+}
diff --git a/src/Renderer/HtmlEngine.php b/src/Renderer/HtmlEngine.php
index 4a48e1f0..75343bbd 100644
--- a/src/Renderer/HtmlEngine.php
+++ b/src/Renderer/HtmlEngine.php
@@ -29,6 +29,6 @@ class HtmlEngine implements EngineInterface
      */
     public function canRender($path)
     {
-        return strpos($path, '.html') && file_exists($path);
+        return strpos($path, '.htm') && file_exists($path);
     }
 }
diff --git a/src/Renderer/Renderer.php b/src/Renderer/Renderer.php
index bf3d5609..de31ca74 100644
--- a/src/Renderer/Renderer.php
+++ b/src/Renderer/Renderer.php
@@ -2,12 +2,11 @@
 
 namespace Engelsystem\Renderer;
 
-use ErrorException;
+use Psr\Log\LoggerAwareTrait;
 
 class Renderer
 {
-    /** @var self */
-    protected static $instance;
+    use LoggerAwareTrait;
 
     /** @var EngineInterface[] */
     protected $renderer = [];
@@ -29,7 +28,10 @@ class Renderer
             return $renderer->get($template, $data);
         }
 
-        engelsystem_error('Unable to find a renderer for template file &laquo;' . $template . '&raquo;.');
+        if ($this->logger) {
+            $this->logger->error('Unable to find a renderer for template file "{file}"', ['file' => $template]);
+        }
+
         return '';
     }
 
@@ -42,21 +44,4 @@ class Renderer
     {
         $this->renderer[] = $renderer;
     }
-
-    /**
-     * @return self
-     * @throws ErrorException
-     */
-    public static function getInstance()
-    {
-        return self::$instance;
-    }
-
-    /**
-     * @param self $instance
-     */
-    public static function setInstance($instance)
-    {
-        self::$instance = $instance;
-    }
 }
diff --git a/src/Routing/UrlGenerator.php b/src/Routing/UrlGenerator.php
index 8dc464c6..6df52425 100644
--- a/src/Routing/UrlGenerator.php
+++ b/src/Routing/UrlGenerator.php
@@ -2,8 +2,6 @@
 
 namespace Engelsystem\Routing;
 
-use Engelsystem\Http\Request;
-
 class UrlGenerator
 {
     /**
@@ -11,10 +9,10 @@ class UrlGenerator
      * @param array  $parameters
      * @return string
      */
-    public static function to($path, $parameters = [])
+    public function to($path, $parameters = [])
     {
         $path = '/' . ltrim($path, '/');
-        $request = Request::getInstance();
+        $request = app('request');
         $uri = $request->getUriForPath($path);
 
         if (!empty($parameters) && is_array($parameters)) {
diff --git a/src/helpers.php b/src/helpers.php
index 24f93f2c..de303963 100644
--- a/src/helpers.php
+++ b/src/helpers.php
@@ -1,6 +1,7 @@
 <?php
 // Some useful functions
 
+use Engelsystem\Application;
 use Engelsystem\Config\Config;
 use Engelsystem\Http\Request;
 use Engelsystem\Renderer\Renderer;
@@ -8,6 +9,21 @@ use Engelsystem\Routing\UrlGenerator;
 use Symfony\Component\HttpFoundation\Session\SessionInterface;
 
 /**
+ * Get the global app instance
+ *
+ * @param string $id
+ * @return mixed
+ */
+function app($id = null)
+{
+    if (is_null($id)) {
+        return Application::getInstance();
+    }
+
+    return Application::getInstance()->get($id);
+}
+
+/**
  * Get or set config values
  *
  * @param string|array $key
@@ -16,15 +32,18 @@ use Symfony\Component\HttpFoundation\Session\SessionInterface;
  */
 function config($key = null, $default = null)
 {
+    $config = app('config');
+
     if (empty($key)) {
-        return Config::getInstance();
+        return $config;
     }
 
     if (is_array($key)) {
-        Config::getInstance()->set($key);
+        $config->set($key);
+        return true;
     }
 
-    return Config::getInstance()->get($key, $default);
+    return $config->get($key, $default);
 }
 
 /**
@@ -34,7 +53,7 @@ function config($key = null, $default = null)
  */
 function request($key = null, $default = null)
 {
-    $request = Request::getInstance();
+    $request = app('request');
 
     if (is_null($key)) {
         return $request;
@@ -50,7 +69,7 @@ function request($key = null, $default = null)
  */
 function session($key = null, $default = null)
 {
-    $session = request()->getSession();
+    $session = app('session');
 
     if (is_null($key)) {
         return $session;
@@ -66,7 +85,7 @@ function session($key = null, $default = null)
  */
 function view($template = null, $data = null)
 {
-    $renderer = Renderer::getInstance();
+    $renderer = app('renderer');
 
     if (is_null($template)) {
         return $renderer;
@@ -78,9 +97,15 @@ function view($template = null, $data = null)
 /**
  * @param string $path
  * @param array  $parameters
- * @return string
+ * @return UrlGenerator|string
  */
-function url($path, $parameters = [])
+function url($path = null, $parameters = [])
 {
-    return UrlGenerator::to($path, $parameters);
+    $urlGenerator = app('routing.urlGenerator');
+
+    if (is_null($path)) {
+        return $urlGenerator;
+    }
+
+    return $urlGenerator->to($path, $parameters);
 }
diff --git a/test/model/LogEntriesModelTest.php b/test/model/LogEntriesModelTest.php
deleted file mode 100644
index 25d46fc4..00000000
--- a/test/model/LogEntriesModelTest.php
+++ /dev/null
@@ -1,38 +0,0 @@
-<?php
-namespace Engelsystem\Test;
-
-use \PHPUnit\Framework\TestCase;
-
-class LogEntriesModelTest extends TestCase
-{
-
-    public function create_LogEntry()
-    {
-        LogEntry_create('test', 'test');
-    }
-
-    public function test_LogEntry_create()
-    {
-        $count = count(LogEntries());
-        $this->assertNotFalse(LogEntry_create('test', 'test_LogEntry_create'));
-        
-        // There should be one more log entry now
-        $this->assertEquals(count(LogEntries()), $count + 1);
-    }
-
-    public function test_LogEntries_clear_all()
-    {
-        $this->create_LogEntry();
-        $this->assertTrue(count(LogEntries()) > 0);
-        $this->assertNotFalse(LogEntries_clear_all());
-        $this->assertEquals(count(LogEntries()), 0);
-    }
-
-    /**
-     * @after
-     */
-    public function teardown()
-    {
-        LogEntries_clear_all();
-    }
-}
diff --git a/tests/Feature/Logger/EngelsystemLoggerTest.php b/tests/Feature/Logger/EngelsystemLoggerTest.php
new file mode 100644
index 00000000..63a01318
--- /dev/null
+++ b/tests/Feature/Logger/EngelsystemLoggerTest.php
@@ -0,0 +1,150 @@
+<?php
+
+namespace Engelsystem\Test\Logger;
+
+use Engelsystem\Logger\EngelsystemLogger;
+use PHPUnit\Framework\TestCase;
+use Psr\Log\InvalidArgumentException;
+use Psr\Log\LoggerInterface;
+use Psr\Log\LogLevel;
+
+class EngelsystemLoggerTest extends TestCase
+{
+    public static function setUpBeforeClass()
+    {
+        require_once __DIR__ . '/../../../includes/engelsystem_provider.php';
+    }
+
+    /**
+     * @return LoggerInterface
+     */
+    public function getLogger()
+    {
+        return new EngelsystemLogger();
+    }
+
+    public function testImplements()
+    {
+        $this->assertInstanceOf('Psr\Log\LoggerInterface', $this->getLogger());
+    }
+
+    /**
+     * @return string[]
+     */
+    public function provideLogLevels()
+    {
+        return [
+            [LogLevel::ALERT],
+            [LogLevel::CRITICAL],
+            [LogLevel::DEBUG],
+            [LogLevel::EMERGENCY],
+            [LogLevel::ERROR],
+            [LogLevel::INFO],
+            [LogLevel::NOTICE],
+            [LogLevel::WARNING],
+        ];
+    }
+
+    /**
+     * @dataProvider provideLogLevels
+     * @param string $level
+     */
+    public function testAllLevels($level)
+    {
+        $logger = $this->getLogger();
+
+        LogEntries_clear_all();
+
+        $logger->log($level, 'First log message');
+        $logger->{$level}('Second log message');
+
+        $entries = LogEntries();
+        $this->assertCount(2, $entries);
+    }
+
+    public function testContextReplacement()
+    {
+        $logger = $this->getLogger();
+        LogEntries_clear_all();
+
+        $logger->log(LogLevel::INFO, 'My username is {username}', ['username' => 'Foo']);
+
+        $entry = $this->getLastEntry();
+        $this->assertEquals('My username is Foo', $entry['message']);
+        $this->assertEquals(LogLevel::INFO, $entry['level']);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function provideContextReplaceValues()
+    {
+        return [
+            ['Data and {context}', [], 'Data and {context}'],
+            ['Data and {context}', ['context' => null], 'Data and '],
+            ['Data and {context}', ['context' => new \stdClass()], 'Data and {context}'],
+            ['Some user asked: {question}', ['question' => 'Foo?'], 'Some user asked: Foo?'],
+        ];
+    }
+
+    /**
+     * @dataProvider provideContextReplaceValues
+     *
+     * @param string   $message
+     * @param string[] $context
+     * @param string   $expected
+     */
+    public function testContextReplaceValues($message, $context, $expected)
+    {
+        $logger = $this->getLogger();
+        $logger->log(LogLevel::INFO, $message, $context);
+
+        $entry = $this->getLastEntry();
+        $this->assertEquals($expected, $entry['message']);
+    }
+
+    public function testContextToString()
+    {
+        $logger = $this->getLogger();
+        LogEntries_clear_all();
+
+        $mock = $this->getMockBuilder('someDataProvider')
+            ->setMethods(['__toString'])
+            ->getMock();
+
+        $mock->expects($this->atLeastOnce())
+            ->method('__toString')
+            ->will($this->returnValue('FooBar'));
+
+        $logger->log(LogLevel::INFO, 'Some data and {context}', ['context' => $mock]);
+
+        $entry = $this->getLastEntry();
+        $this->assertEquals('Some data and FooBar', $entry['message']);
+    }
+
+    /**
+     * @expectedException InvalidArgumentException
+     */
+    public function testThrowExceptionOnInvalidLevel()
+    {
+        $logger = $this->getLogger();
+
+        $logger->log('This log level should never be defined', 'Some message');
+    }
+
+    /**
+     * @return array
+     */
+    public function getLastEntry()
+    {
+        $entries = LogEntries();
+        $entry = array_pop($entries);
+
+        return $entry;
+    }
+
+    public function tearDown()
+    {
+        LogEntries_clear_all();
+    }
+}
diff --git a/tests/Feature/model/LogEntriesModelTest.php b/tests/Feature/model/LogEntriesModelTest.php
new file mode 100644
index 00000000..6d7b0ebc
--- /dev/null
+++ b/tests/Feature/model/LogEntriesModelTest.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace Engelsystem\Test;
+
+use PHPUnit\Framework\TestCase;
+use Psr\Log\LogLevel;
+
+class LogEntriesModelTest extends TestCase
+{
+    public static function setUpBeforeClass()
+    {
+        require_once __DIR__ . '/../../../includes/engelsystem_provider.php';
+    }
+
+    public function testCreateLogEntry()
+    {
+        LogEntries_clear_all();
+        $count = count(LogEntries());
+        $this->assertNotFalse(LogEntry_create(LogLevel::WARNING, 'test_LogEntry_create'));
+
+        // There should be one more log entry now
+        $this->assertEquals(count(LogEntries()), $count + 1);
+    }
+
+    public function testClearAllLogEntries()
+    {
+        LogEntry_create(LogLevel::WARNING, 'test');
+        $this->assertTrue(count(LogEntries()) > 0);
+
+        $this->assertNotFalse(LogEntries_clear_all());
+        $this->assertCount(0, LogEntries());
+    }
+
+    public function tearDown()
+    {
+        LogEntries_clear_all();
+    }
+}
diff --git a/test/model/RoomModelTest.php b/tests/Feature/model/RoomModelTest.php
index 135a6108..96be84a2 100644
--- a/test/model/RoomModelTest.php
+++ b/tests/Feature/model/RoomModelTest.php
@@ -1,13 +1,18 @@
 <?php
+
 namespace Engelsystem\Test;
 
-use \PHPUnit\Framework\TestCase;
+use PHPUnit\Framework\TestCase;
 
 class RoomModelTest extends TestCase
 {
-
     private $room_id = null;
 
+    public static function setUpBeforeClass()
+    {
+        require_once __DIR__ . '/../../../includes/engelsystem_provider.php';
+    }
+
     public function create_Room()
     {
         $this->room_id = Room_create('test', false, true, '');
@@ -16,20 +21,17 @@ class RoomModelTest extends TestCase
     public function test_Room()
     {
         $this->create_Room();
-        
+
         $room = Room($this->room_id);
-        
+
         $this->assertNotFalse($room);
         $this->assertNotNull($room);
         $this->assertEquals($room['Name'], 'test');
-        
-        $this->assertNull(Room(- 1));
+
+        $this->assertNull(Room(-1));
     }
 
-    /**
-     * @after
-     */
-    public function teardown()
+    public function tearDown()
     {
         if ($this->room_id != null) {
             Room_delete($this->room_id);
diff --git a/tests/Unit/ApplicationTest.php b/tests/Unit/ApplicationTest.php
new file mode 100644
index 00000000..77429f44
--- /dev/null
+++ b/tests/Unit/ApplicationTest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Engelsystem\Test\Config;
+
+use Engelsystem\Application;
+use Engelsystem\Container\Container;
+use PHPUnit\Framework\TestCase;
+use Psr\Container\ContainerInterface;
+
+class ApplicationTest extends TestCase
+{
+    /**
+     * @covers       \Engelsystem\Application::__construct
+     * @covers       \Engelsystem\Application::registerBaseBindings
+     */
+    public function testConstructor()
+    {
+        $app = new Application();
+
+        $this->assertInstanceOf(Container::class, $app);
+        $this->assertInstanceOf(ContainerInterface::class, $app);
+        $this->assertSame($app, $app->get('app'));
+        $this->assertSame($app, $app->get('container'));
+        $this->assertSame($app, $app->get(Container::class));
+        $this->assertSame($app, $app->get(Application::class));
+        $this->assertSame($app, $app->get(ContainerInterface::class));
+        $this->assertSame($app, Container::getInstance());
+    }
+}
diff --git a/tests/Unit/Config/ConfigTest.php b/tests/Unit/Config/ConfigTest.php
new file mode 100644
index 00000000..ce11ebd6
--- /dev/null
+++ b/tests/Unit/Config/ConfigTest.php
@@ -0,0 +1,115 @@
+<?php
+
+namespace Engelsystem\Test\Config;
+
+use Engelsystem\Config\Config;
+use PHPUnit\Framework\TestCase;
+
+class ConfigTest extends TestCase
+{
+    /**
+     * @covers \Engelsystem\Config\Config::get
+     */
+    public function testGet()
+    {
+        $config = new Config();
+
+        $config->set('test', 'FooBar');
+        $this->assertEquals(['test' => 'FooBar'], $config->get(null));
+        $this->assertEquals('FooBar', $config->get('test'));
+
+        $this->assertEquals('defaultValue', $config->get('notExisting', 'defaultValue'));
+
+        $this->assertNull($config->get('notExisting'));
+    }
+
+    /**
+     * @covers \Engelsystem\Config\Config::set
+     */
+    public function testSet()
+    {
+        $config = new Config();
+
+        $config->set('test', 'FooBar');
+        $this->assertEquals('FooBar', $config->get('test'));
+
+        $config->set([
+            'name' => 'Engelsystem',
+            'mail' => ['user' => 'test'],
+        ]);
+        $this->assertEquals('Engelsystem', $config->get('name'));
+        $this->assertEquals(['user' => 'test'], $config->get('mail'));
+    }
+
+    /**
+     * @covers \Engelsystem\Config\Config::has
+     */
+    public function testHas()
+    {
+        $config = new Config();
+
+        $this->assertFalse($config->has('test'));
+
+        $config->set('test', 'FooBar');
+        $this->assertTrue($config->has('test'));
+    }
+
+    /**
+     * @covers \Engelsystem\Config\Config::remove
+     */
+    public function testRemove()
+    {
+        $config = new Config();
+        $config->set(['foo' => 'bar', 'test' => '123']);
+
+        $config->remove('foo');
+        $this->assertEquals(['test' => '123'], $config->get(null));
+    }
+
+    /**
+     * @covers \Engelsystem\Config\Config::__get
+     */
+    public function testMagicGet()
+    {
+        $config = new Config();
+
+        $config->set('test', 'FooBar');
+        $this->assertEquals('FooBar', $config->test);
+    }
+
+    /**
+     * @covers \Engelsystem\Config\Config::__set
+     */
+    public function testMagicSet()
+    {
+        $config = new Config();
+
+        $config->test = 'FooBar';
+        $this->assertEquals('FooBar', $config->get('test'));
+    }
+
+    /**
+     * @covers \Engelsystem\Config\Config::__isset
+     */
+    public function testMagicIsset()
+    {
+        $config = new Config();
+
+        $this->assertFalse(isset($config->test));
+
+        $config->set('test', 'FooBar');
+        $this->assertTrue(isset($config->test));
+    }
+
+    /**
+     * @covers \Engelsystem\Config\Config::__unset
+     */
+    public function testMagicUnset()
+    {
+        $config = new Config();
+        $config->set(['foo' => 'bar', 'test' => '123']);
+
+        unset($config->foo);
+        $this->assertEquals(['test' => '123'], $config->get(null));
+    }
+}
diff --git a/tests/Unit/Container/ContainerTest.php b/tests/Unit/Container/ContainerTest.php
new file mode 100644
index 00000000..89c34209
--- /dev/null
+++ b/tests/Unit/Container/ContainerTest.php
@@ -0,0 +1,104 @@
+<?php
+
+namespace Engelsystem\Test\Config;
+
+use Engelsystem\Container\Container;
+use PHPUnit\Framework\TestCase;
+
+class ContainerTest extends TestCase
+{
+    /**
+     * @covers \Engelsystem\Container\Container::get
+     */
+    public function testGet()
+    {
+        $container = new Container();
+        $class = new class
+        {
+        };
+
+        $container->instance('foo', $class);
+        $this->assertSame($class, $container->get('foo'));
+    }
+
+    /**
+     * @covers \Engelsystem\Container\Container::get
+     * @expectedException \Engelsystem\Container\NotFoundException
+     */
+    public function testGetException()
+    {
+        $container = new Container();
+
+        $container->get('not.registered.service');
+    }
+
+    /**
+     * @covers \Engelsystem\Container\Container::instance
+     * @covers \Engelsystem\Container\Container::resolve
+     */
+    public function testInstance()
+    {
+        $container = new Container();
+        $class = new class
+        {
+        };
+
+        $container->instance('foo', $class);
+        $this->assertSame($class, $container->get('foo'));
+    }
+
+    /**
+     * @covers \Engelsystem\Container\Container::has
+     */
+    public function testHas()
+    {
+        $container = new Container();
+
+        $this->assertFalse($container->has('test'));
+
+        $class = new class
+        {
+        };
+
+        $container->instance('test', $class);
+        $this->assertTrue($container->has('test'));
+    }
+
+    /**
+     * @covers \Engelsystem\Container\Container::singleton
+     */
+    public function testSingleton()
+    {
+        $container = new Container();
+        $class = new class
+        {
+        };
+
+        $container->singleton('foo', $class);
+        $this->assertSame($class, $container->get('foo'));
+        $this->assertSame($class, $container->get('foo'));
+    }
+
+    /**
+     * @covers \Engelsystem\Container\Container::setInstance
+     * @covers \Engelsystem\Container\Container::getInstance
+     */
+    public function testContainerSingleton()
+    {
+        // Ensure that no container has been initialized
+        $reflection = new \ReflectionProperty(Container::class, 'instance');
+        $reflection->setAccessible(true);
+        $reflection->setValue(null, null);
+        $reflection->setAccessible(false);
+
+        $container0 = new Container();
+        $container = Container::getInstance();
+
+        $this->assertNotSame($container0, $container);
+
+        $container1 = new Container;
+        Container::setInstance($container1);
+
+        $this->assertSame($container1, Container::getInstance());
+    }
+}
diff --git a/tests/Unit/HelpersTest.php b/tests/Unit/HelpersTest.php
new file mode 100644
index 00000000..d9782888
--- /dev/null
+++ b/tests/Unit/HelpersTest.php
@@ -0,0 +1,152 @@
+<?php
+
+namespace Engelsystem\Test\Config;
+
+use Engelsystem\Application;
+use Engelsystem\Config\Config;
+use Engelsystem\Container\Container;
+use Engelsystem\Http\Request;
+use Engelsystem\Renderer\Renderer;
+use Engelsystem\Routing\UrlGenerator;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpFoundation\Session\Session;
+
+class HelpersTest extends TestCase
+{
+    /**
+     * @covers \app
+     */
+    public function testApp()
+    {
+        $class = new class
+        {
+        };
+
+        $appMock = $this->getAppMock('some.name', $class);
+
+        $this->assertEquals($appMock, app());
+        $this->assertEquals($class, app('some.name'));
+    }
+
+    /**
+     * @covers \config
+     */
+    public function testConfig()
+    {
+        $configMock = $this->getMockBuilder(Config::class)
+            ->getMock();
+
+        $this->getAppMock('config', $configMock);
+        $this->assertEquals($configMock, config());
+
+        $configMock->expects($this->once())
+            ->method('set')
+            ->with(['foo' => 'bar']);
+
+        $this->assertTrue(config(['foo' => 'bar']));
+
+        $configMock->expects($this->once())
+            ->method('get')
+            ->with('mail')
+            ->willReturn(['user' => 'FooBar']);
+
+        $this->assertEquals(['user' => 'FooBar'], config('mail'));
+    }
+
+    /**
+     * @covers \request
+     */
+    public function testRequest()
+    {
+        $requestMock = $this->getMockBuilder(Request::class)
+            ->getMock();
+
+        $this->getAppMock('request', $requestMock);
+        $this->assertEquals($requestMock, request());
+
+        $requestMock->expects($this->once())
+            ->method('input')
+            ->with('requestKey')
+            ->willReturn('requestValue');
+
+        $this->assertEquals('requestValue', request('requestKey'));
+    }
+
+    /**
+     * @covers \session
+     */
+    public function testSession()
+    {
+        $sessionMock = $this->getMockBuilder(Session::class)
+            ->getMock();
+
+        $this->getAppMock('session', $sessionMock);
+        $this->assertEquals($sessionMock, session());
+
+        $sessionMock->expects($this->once())
+            ->method('get')
+            ->with('someKey')
+            ->willReturn('someValue');
+
+        $this->assertEquals('someValue', session('someKey'));
+    }
+
+    /**
+     * @covers \view
+     */
+    public function testView()
+    {
+        $rendererMock = $this->getMockBuilder(Renderer::class)
+            ->getMock();
+
+        $this->getAppMock('renderer', $rendererMock);
+        $this->assertEquals($rendererMock, view());
+
+        $rendererMock->expects($this->once())
+            ->method('render')
+            ->with('template.name', ['template' => 'data'])
+            ->willReturn('rendered template');
+
+        $this->assertEquals('rendered template', view('template.name', ['template' => 'data']));
+    }
+
+    /**
+     * @covers \url
+     */
+    public function testUrl()
+    {
+        $urlGeneratorMock = $this->getMockBuilder(UrlGenerator::class)
+            ->getMock();
+
+        $this->getAppMock('routing.urlGenerator', $urlGeneratorMock);
+        $this->assertEquals($urlGeneratorMock, url());
+
+        $urlGeneratorMock->expects($this->once())
+            ->method('to')
+            ->with('foo/bar', ['param' => 'value'])
+            ->willReturn('http://lorem.ipsum/foo/bar?param=value');
+
+        $this->assertEquals('http://lorem.ipsum/foo/bar?param=value', url('foo/bar', ['param' => 'value']));
+    }
+
+    /**
+     * @param string $alias
+     * @param object $object
+     * @return Application|\PHPUnit_Framework_MockObject_MockObject
+     */
+    protected function getAppMock($alias, $object)
+    {
+        $appMock = $this->getMockBuilder(Container::class)
+            ->getMock();
+
+        $appMock->expects($this->atLeastOnce())
+            ->method('get')
+            ->with($alias)
+            ->willReturn($object);
+
+        /** @var $appMock Application */
+        Application::setInstance($appMock);
+
+        return $appMock;
+    }
+}
diff --git a/tests/Unit/Renderer/HtmlEngineTest.php b/tests/Unit/Renderer/HtmlEngineTest.php
new file mode 100644
index 00000000..0b317b72
--- /dev/null
+++ b/tests/Unit/Renderer/HtmlEngineTest.php
@@ -0,0 +1,67 @@
+<?php
+
+namespace Engelsystem\Test\Config;
+
+use Engelsystem\Renderer\HtmlEngine;
+use PHPUnit\Framework\TestCase;
+
+class HtmlEngineTest extends TestCase
+{
+    /** @var string[] */
+    protected $tmpFileNames = [];
+
+    /**
+     * @covers \Engelsystem\Renderer\HtmlEngine::get
+     */
+    public function testGet()
+    {
+        $engine = new HtmlEngine();
+
+        $file = $this->createTempFile('<div>%main_content%</div>');
+
+        $data = $engine->get($file, ['main_content' => 'Lorem ipsum dolor sit']);
+        $this->assertEquals('<div>Lorem ipsum dolor sit</div>', $data);
+    }
+
+    /**
+     * @covers \Engelsystem\Renderer\HtmlEngine::canRender
+     */
+    public function testCanRender()
+    {
+        $engine = new HtmlEngine();
+
+        $this->assertFalse($engine->canRender('/dev/null'));
+
+        $file = $this->createTempFile();
+        $this->assertTrue($engine->canRender($file));
+
+        $htmFile = $this->createTempFile('', '.htm');
+        $this->assertTrue($engine->canRender($htmFile));
+    }
+
+    /**
+     * @param string $content
+     * @param string $extension
+     * @return string
+     */
+    protected function createTempFile($content = '', $extension = '.html')
+    {
+        $tmpFileName = tempnam(sys_get_temp_dir(), 'EngelsystemUnitTest');
+
+        $fileName = $tmpFileName . $extension;
+        rename($tmpFileName, $fileName);
+
+        file_put_contents($fileName, $content);
+
+        $this->tmpFileNames[] = $fileName;
+
+        return $fileName;
+    }
+
+    public function tearDown()
+    {
+        foreach ($this->tmpFileNames as $fileName) {
+            unlink($fileName);
+        }
+    }
+}
diff --git a/tests/Unit/Renderer/RendererTest.php b/tests/Unit/Renderer/RendererTest.php
new file mode 100644
index 00000000..b0238078
--- /dev/null
+++ b/tests/Unit/Renderer/RendererTest.php
@@ -0,0 +1,55 @@
+<?php
+
+namespace Engelsystem\Test\Config;
+
+use Engelsystem\Renderer\EngineInterface;
+use Engelsystem\Renderer\Renderer;
+use PHPUnit\Framework\TestCase;
+use Psr\Log\LoggerInterface;
+
+class RendererTest extends TestCase
+{
+    public function testGet()
+    {
+        $renderer = new Renderer();
+
+        $nullRenderer = $this->getMockForAbstractClass(EngineInterface::class);
+
+        $nullRenderer->expects($this->atLeastOnce())
+            ->method('canRender')
+            ->willReturn(false);
+        $renderer->addRenderer($nullRenderer);
+
+        $mockRenderer = $this->getMockForAbstractClass(EngineInterface::class);
+
+        $mockRenderer->expects($this->atLeastOnce())
+            ->method('canRender')
+            ->with('foo.template')
+            ->willReturn(true);
+
+        $mockRenderer->expects($this->atLeastOnce())
+            ->method('get')
+            ->with('foo.template', ['lorem' => 'ipsum'])
+            ->willReturn('Rendered content');
+
+        $renderer->addRenderer($mockRenderer);
+        $data = $renderer->render('foo.template', ['lorem' => 'ipsum']);
+
+        $this->assertEquals('Rendered content', $data);
+    }
+
+    public function testError()
+    {
+        $renderer = new Renderer();
+
+        $loggerMock = $this->getMockForAbstractClass(LoggerInterface::class);
+        $loggerMock
+            ->expects($this->once())
+            ->method('error');
+
+        $renderer->setLogger($loggerMock);
+
+        $data = $renderer->render('testing.template');
+        $this->assertEquals('', $data);
+    }
+}
diff --git a/tests/Unit/Routing/UrlGeneratorTest.php b/tests/Unit/Routing/UrlGeneratorTest.php
new file mode 100644
index 00000000..fc23520a
--- /dev/null
+++ b/tests/Unit/Routing/UrlGeneratorTest.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace Engelsystem\Test\Config;
+
+use Engelsystem\Application;
+use Engelsystem\Container\Container;
+use Engelsystem\Http\Request;
+use Engelsystem\Routing\UrlGenerator;
+use PHPUnit\Framework\TestCase;
+
+class UrlGeneratorTest extends TestCase
+{
+    public function provideLinksTo()
+    {
+        return [
+            ['/foo/path', '/foo/path', 'http://foo.bar/foo/path', [], 'http://foo.bar/foo/path'],
+            ['foo', '/foo', 'https://foo.bar/foo', [], 'https://foo.bar/foo'],
+            ['foo', '/foo', 'http://f.b/foo', ['test' => 'abc', 'bla' => 'foo'], 'http://f.b/foo?test=abc&bla=foo'],
+        ];
+    }
+
+    /**
+     * @dataProvider provideLinksTo
+     * @covers       \Engelsystem\Routing\UrlGenerator::to
+     *
+     * @param string   $path
+     * @param string   $willReturn
+     * @param string   $urlToPath
+     * @param string[] $arguments
+     * @param string   $expectedUrl
+     */
+    public function testTo($urlToPath, $path, $willReturn, $arguments, $expectedUrl)
+    {
+        $app = new Container();
+        $urlGenerator = new UrlGenerator();
+        Application::setInstance($app);
+
+        $request = $this->getMockBuilder(Request::class)
+            ->getMock();
+
+        $request->expects($this->once())
+            ->method('getUriForPath')
+            ->with($path)
+            ->willReturn($willReturn);
+
+        $app->instance('request', $request);
+
+        $url = $urlGenerator->to($urlToPath, $arguments);
+        $this->assertEquals($expectedUrl, $url);
+    }
+}