diff --git a/composer.json b/composer.json
index ffa88b4..ef14257 100644
--- a/composer.json
+++ b/composer.json
@@ -58,6 +58,7 @@
     },
     "scripts": {
         "cs-check": "php-cs-fixer fix --dry-run --diff --config=.php-cs.php",
-        "cs-fix": "php-cs-fixer fix --diff --config=.php-cs.php"
+        "cs-fix": "php-cs-fixer fix --diff --config=.php-cs.php",
+        "test": "bin/phpunit tests"
     }
 }
diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index cd03c05..3ee2da1 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -13,27 +13,27 @@
  */
 final class Configuration implements ConfigurationInterface
 {
-    const READ_PREFERENCE_VALID_OPTIONS = ['primary', 'primaryPreferred', 'secondary', 'secondaryPreferred', 'nearest'];
+    private const READ_PREFERENCE_VALID_OPTIONS = ['primary', 'primaryPreferred', 'secondary', 'secondaryPreferred', 'nearest'];
 
     /**
      * {@inheritdoc}
      */
-    public function getConfigTreeBuilder()
+    public function getConfigTreeBuilder(): TreeBuilder
     {
         $treeBuilder = new TreeBuilder('mongo_db_bundle');
         $rootBuilder = \method_exists(TreeBuilder::class, 'getRootNode')
             ? $treeBuilder->getRootNode()
             : $treeBuilder->root('mongo_db_bundle');
 
-        $this->addDataCollection($rootBuilder->children());
-        $this->addClients($rootBuilder->children());
-        $this->addConnections($rootBuilder->children());
-        $this->addDriversOptionFactory($rootBuilder->children());
+        self::addDataCollection($rootBuilder->children());
+        self::addClients($rootBuilder->children());
+        self::addConnections($rootBuilder->children());
+        self::addDriversOption($rootBuilder->children());
 
         return $treeBuilder;
     }
 
-    private function addDataCollection(NodeBuilder $builder)
+    private static function addDataCollection(NodeBuilder $builder): void
     {
         $builder
             ->booleanNode('data_collection')
@@ -41,7 +41,7 @@ private function addDataCollection(NodeBuilder $builder)
             ->info('Disables Data Collection if needed');
     }
 
-    private function addClients(NodeBuilder $builder)
+    private static function addClients(NodeBuilder $builder): void
     {
         $clientsBuilder = $builder
             ->arrayNode('clients')
@@ -51,7 +51,7 @@ private function addClients(NodeBuilder $builder)
             ->prototype('array')
             ->children();
 
-        $this->addClientsHosts($clientsBuilder);
+        self::addClientsHosts($clientsBuilder);
 
         $clientsBuilder
             ->scalarNode('uri')
@@ -91,7 +91,7 @@ private function addClients(NodeBuilder $builder)
             ->defaultNull();
     }
 
-    private function addClientsHosts(NodeBuilder $builder)
+    private static function addClientsHosts(NodeBuilder $builder): void
     {
         $hostsBuilder = $builder
             ->arrayNode('hosts')
@@ -108,26 +108,13 @@ private function addClientsHosts(NodeBuilder $builder)
             ->defaultValue(27017);
     }
 
-    private function addDriverOptions(NodeBuilder $builder)
+    private static function addDriversOption(NodeBuilder $builder): void
     {
-        $driverOptionsBuilder = $builder
-            ->arrayNode('driverOptions')
-            ->info('Available options for driver')
-            ->children();
-
-        $driverOptionsBuilder
-            ->variableNode('context')
-            ->defaultValue([])
-            ->info('Service id name');
-    }
-
-    private function addDriversOptionFactory(NodeBuilder $builder)
-    {
-        $connectionBuilder = $builder
+        $builder
             ->scalarNode('driverOptions');
     }
 
-    private function addConnections(NodeBuilder $builder)
+    private static function addConnections(NodeBuilder $builder): void
     {
         $connectionBuilder = $builder
             ->arrayNode('connections')
diff --git a/src/Models/ClientConfiguration.php b/src/Models/ClientConfiguration.php
index 4c60410..8381071 100644
--- a/src/Models/ClientConfiguration.php
+++ b/src/Models/ClientConfiguration.php
@@ -120,7 +120,7 @@ private function cleanOptions(array $options): array
     {
         return array_filter(
             $options,
-            function ($value) {
+            function ($value): bool {
                 return ! empty($value) || \is_int($value) || \is_bool($value) || \is_float($value);
             }
         );
diff --git a/src/Services/ClientRegistry.php b/src/Services/ClientRegistry.php
index 2dcd638..8707fbc 100644
--- a/src/Services/ClientRegistry.php
+++ b/src/Services/ClientRegistry.php
@@ -34,13 +34,6 @@ final class ClientRegistry
     /** @var DriverOptionsInterface */
     private $driverOptionsService;
 
-    /**
-     * ClientRegistry constructor.
-     *
-     * @param EventDispatcherInterface $eventDispatcher
-     * @param bool $debug
-     * @param DriverOptionsInterface|null $driverOptionsService
-     */
     public function __construct(
         EventDispatcherInterface $eventDispatcher,
         bool $debug,
@@ -53,25 +46,13 @@ public function __construct(
         $this->driverOptionsService = $driverOptionsService;
     }
 
-    /**
-     * @param array $configurations
-     */
-    public function addClientsConfigurations(array $configurations)
+    public function addClientsConfigurations(array $configurations): void
     {
         foreach ($configurations as $name => $conf) {
-            $this->addClientConfiguration($name, $conf);
+            $this->configurations[$name] = $this->buildClientConfiguration($conf);
         }
     }
 
-    /**
-     * @param string $name
-     * @param array  $conf
-     */
-    private function addClientConfiguration(string $name, array $conf)
-    {
-        $this->configurations[$name] = $this->buildClientConfiguration($conf);
-    }
-
     /**
      * @param array $conf
      *
@@ -80,7 +61,7 @@ private function addClientConfiguration(string $name, array $conf)
     private function buildClientConfiguration(array $conf): ClientConfiguration
     {
         if (! $conf['uri']) {
-            $conf['uri'] = $this->buildConnectionUri($conf['hosts']);
+            $conf['uri'] = self::buildConnectionUri($conf['hosts']);
         }
 
         $conf['driverOptions'] = [];
@@ -103,17 +84,12 @@ private function buildClientConfiguration(array $conf): ClientConfiguration
         );
     }
 
-    /**
-     * @param array $hosts
-     *
-     * @return string
-     */
-    private function buildConnectionUri(array $hosts): string
+    private static function buildConnectionUri(array $hosts): string
     {
         return 'mongodb://' . implode(
             ',',
             array_map(
-                function (array $host) {
+                static function (array $host): string {
                     return sprintf('%s:%d', $host['host'], $host['port']);
                 },
                 $hosts
@@ -121,32 +97,17 @@ function (array $host) {
         );
     }
 
-    /**
-     * @param string $name
-     * @param string $databaseName
-     *
-     * @return Client
-     */
     public function getClientForDatabase(string $name, string $databaseName): Client
     {
         return $this->getClient($name, $databaseName);
     }
 
-    /**
-     * @return array
-     */
     public function getClientNames(): array
     {
         return array_keys($this->clients);
     }
 
-    /**
-     * @param string $name
-     * @param string $databaseName
-     *
-     * @return Client
-     */
-    public function getClient(string $name, string $databaseName = null): Client
+    public function getClient(string $name, ?string $databaseName = null): Client
     {
         $clientKey = null !== $databaseName ? $name . '.' . $databaseName : $name;
 
diff --git a/tests/Functional/Capsule/CollectionTest.php b/tests/Functional/Capsule/CollectionTest.php
index eee420f..1aeff8f 100644
--- a/tests/Functional/Capsule/CollectionTest.php
+++ b/tests/Functional/Capsule/CollectionTest.php
@@ -1,6 +1,6 @@
-<?php
+<?php declare(strict_types=1);
 
-declare(strict_types=1);
+namespace Facile\MongoDbBundle\Tests\Functional\Capsule;
 
 use Facile\MongoDbBundle\Capsule\Collection;
 use Facile\MongoDbBundle\Event\QueryEvent;