diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 39643806..a92c4956 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -14,7 +14,7 @@ jobs:
         runs-on: ubuntu-latest
         strategy:
             matrix:
-                php-versions: ['7.2', '7.3', '7.4', '8.0']
+                php-versions: ['7.4', '8.0']
         name: integration-tests (PHP ${{ matrix.php-versions }})
         steps:
             -   uses: actions/checkout@v2
diff --git a/.php_cs.dist b/.php_cs.dist
index ed824215..bc649fc7 100644
--- a/.php_cs.dist
+++ b/.php_cs.dist
@@ -1,33 +1,28 @@
 <?php
 
+declare(strict_types=1);
+
 if (!file_exists(__DIR__.'/src')) {
     exit(0);
 }
 
-return PhpCsFixer\Config::create()
-    ->setRules(
-        [
+$finder = PhpCsFixer\Finder::create()
+    ->in(__DIR__.'/src')
+    ->in(__DIR__.'/tests')
+    ->append([__FILE__]);
+$config = new PhpCsFixer\Config();
+$config->setRules([
             '@Symfony' => true,
-            '@Symfony:risky' => true,
-            '@PHPUnit75Migration:risky' => true,
-            'php_unit_dedicate_assert' => ['target' => 'newest'],
-            'array_syntax' => ['syntax' => 'short'],
-            'fopen_flags' => false,
-            'protected_to_private' => false,
-            'combine_nested_dirname' => true,
+            'declare_strict_types' => true,
             'global_namespace_import' => [
-                'import_classes' => true,
-                'import_constants' => true,
-                'import_functions' => true,
+                'import_classes' => false,
+                'import_functions' => false,
+                'import_constants' => false,
             ],
-            'phpdoc_no_package' => false,
-            'no_superfluous_phpdoc_tags' => false,
-            'ordered_imports' => ['sortAlgorithm' => 'none'],
         ]
     )
     ->setRiskyAllowed(true)
-    ->setFinder(
-        PhpCsFixer\Finder::create()
-            ->in(__DIR__.'/src')
-            ->append([__FILE__])
-    );
+    ->setFinder($finder)
+;
+
+return $config;
diff --git a/Dockerfile b/Dockerfile
index 78be152e..30d7154a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM php:7.2.0-fpm-alpine as php
+FROM php:7.4-fpm-alpine as php
 
 # persistent / runtime deps
 RUN apk add --no-cache \
diff --git a/bors.toml b/bors.toml
index 7a464242..dd3f648c 100644
--- a/bors.toml
+++ b/bors.toml
@@ -1,6 +1,4 @@
 status = [
-    'integration-tests (PHP 7.2)',
-    'integration-tests (PHP 7.3)',
     'integration-tests (PHP 7.4)',
     'integration-tests (PHP 8.0)',
     'linter-check'
diff --git a/composer.json b/composer.json
index a1f03c4d..dadebf56 100644
--- a/composer.json
+++ b/composer.json
@@ -18,17 +18,17 @@
         }
     ],
     "require": {
-        "php": ">=7.2",
+        "php": "^7.4|^8.0",
         "ext-json": "*",
+        "doctrine/orm": "^2.8",
         "meilisearch/meilisearch-php": "^0.17",
         "symfony/filesystem": "^4.0 || ^5.0",
         "symfony/property-access": "^4.0 || ^5.0",
         "symfony/serializer": "^4.0 || ^5.0"
     },
     "require-dev": {
-        "doctrine/doctrine-bundle": "^2.0",
-        "doctrine/orm": "^2.5",
-        "friendsofphp/php-cs-fixer": "^2.16",
+        "doctrine/doctrine-bundle": "^2.3",
+        "friendsofphp/php-cs-fixer": "^2.18",
         "jms/serializer-bundle": "^3.0",
         "nyholm/psr7": "^1.3",
         "phpunit/phpunit": "^8.5",
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index 91ed7c74..cdb576e5 100644
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -12,7 +12,7 @@ if [ "$1" = 'php-fpm' ] || [ "$1" = 'php' ] || [ "$1" = 'bin/console' ]; then
   setfacl -dR -m u:www-data:rwX -m u:"$(whoami)":rwX var
 
   if [ "$APP_ENV" != 'prod' ]; then
-    composer install --prefer-dist --no-progress --no-suggest --no-interaction
+    composer install --prefer-dist --no-progress --no-interaction
   fi
 fi
 
diff --git a/src/Command/IndexCommand.php b/src/Command/IndexCommand.php
index 665a11fc..b3a9aeef 100644
--- a/src/Command/IndexCommand.php
+++ b/src/Command/IndexCommand.php
@@ -1,32 +1,22 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Command;
 
 use MeiliSearch\Bundle\SearchService;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
-use function array_keys;
-use function count;
-use function explode;
 
 /**
  * Class IndexCommand.
- *
- * @package MeiliSearch\Bundle\Command
  */
 abstract class IndexCommand extends Command
 {
-    /** @var SearchService */
-    protected $searchService;
+    protected SearchService $searchService;
 
-    /**
-     * IndexCommand constructor.
-     *
-     * @param SearchService $searchService
-     * @param string|null   $name
-     */
-    public function __construct(SearchService $searchService, string $name = null)
+    public function __construct(SearchService $searchService, ?string $name = null)
     {
         $this->searchService = $searchService;
         parent::__construct($name);
@@ -38,7 +28,7 @@ protected function getEntitiesFromArgs(InputInterface $input, OutputInterface $o
         $indexNames = [];
 
         if ($indexList = $input->getOption('indices')) {
-            $indexNames = explode(',', $indexList);
+            $indexNames = \explode(',', $indexList);
         }
 
         $config = $this->searchService->getConfiguration();
diff --git a/src/Command/MeiliSearchClearCommand.php b/src/Command/MeiliSearchClearCommand.php
index 7d8bcdbd..979eba86 100644
--- a/src/Command/MeiliSearchClearCommand.php
+++ b/src/Command/MeiliSearchClearCommand.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Command;
 
 use Symfony\Component\Console\Input\InputInterface;
@@ -8,17 +10,11 @@
 
 /**
  * Class MeiliSearchClearCommand.
- *
- * @package MeiliSearch\Bundle\Command
  */
 final class MeiliSearchClearCommand extends IndexCommand
 {
-    /** @var string */
     protected static $defaultName = 'meili:clear';
 
-    /**
-     * {@inheritdoc}
-     */
     protected function configure()
     {
         $this
diff --git a/src/Command/MeiliSearchImportCommand.php b/src/Command/MeiliSearchImportCommand.php
index 1e239ae3..daf92649 100644
--- a/src/Command/MeiliSearchImportCommand.php
+++ b/src/Command/MeiliSearchImportCommand.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Command;
 
 use Doctrine\Persistence\ManagerRegistry;
@@ -8,47 +10,19 @@
 use MeiliSearch\Bundle\Model\Aggregator;
 use MeiliSearch\Bundle\SearchService;
 use MeiliSearch\Client;
-use MeiliSearch\Exceptions\ApiException;
-use MeiliSearch\Exceptions\TimeOutException;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\OutputInterface;
-use function array_key_exists;
-use function array_map;
-use function array_merge;
-use function array_unique;
-use function count;
-use function is_subclass_of;
-use function method_exists;
-use function sprintf;
-use function ucfirst;
-use const SORT_REGULAR;
 
 /**
  * Class MeiliSearchImportCommand.
- *
- * @package MeiliSearch\Bundle\Command
  */
 final class MeiliSearchImportCommand extends IndexCommand
 {
-    /**
-     * @var string
-     */
     protected static $defaultName = 'meili:import';
+    protected Client $searchClient;
+    protected ManagerRegistry $managerRegistry;
 
-    /** @var Client */
-    protected $searchClient;
-
-    /** @var ManagerRegistry */
-    protected $managerRegistry;
-
-    /**
-     * MeiliSearchImportCommand constructor.
-     *
-     * @param SearchService   $searchService
-     * @param ManagerRegistry $managerRegistry
-     * @param Client          $searchClient
-     */
     public function __construct(SearchService $searchService, ManagerRegistry $managerRegistry, Client $searchClient)
     {
         parent::__construct($searchService);
@@ -56,9 +30,6 @@ public function __construct(SearchService $searchService, ManagerRegistry $manag
         $this->searchClient = $searchClient;
     }
 
-    /**
-     * {@inheritdoc}
-     */
     protected function configure()
     {
         $this
@@ -72,12 +43,6 @@ protected function configure()
             );
     }
 
-    /**
-     * {@inheritdoc}
-     *
-     * @throws TimeOutException
-     * @throws ApiException
-     */
     protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $entitiesToIndex = $this->getEntitiesFromArgs($input, $output);
@@ -164,11 +129,7 @@ function ($entity) {
         return 0;
     }
 
-    /**
-     * @param array $batch
-     *
-     * @return array
-     *
+    /*
      * @throws TimeOutException
      */
     private function formatIndexingResponse(array $batch): array
diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 4b209241..ce7d1f16 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\DependencyInjection;
 
 use Symfony\Component\Config\Definition\Builder\TreeBuilder;
@@ -7,15 +9,10 @@
 
 /**
  * Class Configuration.
- *
- * @package MeiliSearch\Bundle\DependencyInjection
  */
 final class Configuration implements ConfigurationInterface
 {
-    /**
-     * {@inheritdoc}
-     */
-    public function getConfigTreeBuilder()
+    public function getConfigTreeBuilder(): TreeBuilder
     {
         $treeBuilder = new TreeBuilder('meili_search');
         $rootNode = $treeBuilder->getRootNode();
diff --git a/src/DependencyInjection/MeiliSearchExtension.php b/src/DependencyInjection/MeiliSearchExtension.php
index d94754e6..b68f860c 100644
--- a/src/DependencyInjection/MeiliSearchExtension.php
+++ b/src/DependencyInjection/MeiliSearchExtension.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\DependencyInjection;
 
 use MeiliSearch\Bundle\Engine;
@@ -10,22 +12,18 @@
 use Symfony\Component\DependencyInjection\Loader;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\HttpKernel\DependencyInjection\Extension;
-use function count;
-use function dirname;
 
 /**
  * Class MeiliSearchExtension.
- *
- * @package MeiliSearch\Bundle\DependencyInjection
  */
 final class MeiliSearchExtension extends Extension
 {
     /**
      * {@inheritdoc}
      */
-    public function load(array $configs, ContainerBuilder $container)
+    public function load(array $configs, ContainerBuilder $container): void
     {
-        $loader = new Loader\XmlFileLoader($container, new FileLocator(dirname(__DIR__).'/Resources/config'));
+        $loader = new Loader\XmlFileLoader($container, new FileLocator(\dirname(__DIR__).'/Resources/config'));
         $loader->load('services.xml');
 
         $configuration = new Configuration();
@@ -35,7 +33,7 @@ public function load(array $configs, ContainerBuilder $container)
             $config['prefix'] = $container->getParameter('kernel.environment').'_';
         }
 
-        if (count($doctrineSubscribedEvents = $config['doctrineSubscribedEvents']) > 0) {
+        if (\count($doctrineSubscribedEvents = $config['doctrineSubscribedEvents']) > 0) {
             $container->getDefinition('search.search_indexer_subscriber')->setArgument(1, $doctrineSubscribedEvents);
         } else {
             $container->removeDefinition('search.search_indexer_subscriber');
diff --git a/src/Document/Aggregator.php b/src/Document/Aggregator.php
index d4c797a8..f75b613b 100644
--- a/src/Document/Aggregator.php
+++ b/src/Document/Aggregator.php
@@ -1,13 +1,13 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Document;
 
 use MeiliSearch\Bundle\Model\Aggregator as BaseAggregator;
 
 /**
  * Class Aggregator.
- *
- * @package MeiliSearch\Bundle\Document
  */
 abstract class Aggregator extends BaseAggregator
 {
diff --git a/src/Engine.php b/src/Engine.php
index 9e562386..4ba66b04 100644
--- a/src/Engine.php
+++ b/src/Engine.php
@@ -1,28 +1,20 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle;
 
+use function count;
 use MeiliSearch\Client;
 use MeiliSearch\Exceptions\ApiException;
-use Symfony\Component\Serializer\Exception\ExceptionInterface;
-use function count;
-use function reset;
 
 /**
  * Class Engine.
- *
- * @package MeiliSearch\Bundle
  */
 final class Engine
 {
-    /** @var Client */
-    private $client;
+    private Client $client;
 
-    /**
-     * Engine constructor.
-     *
-     * @param Client $client
-     */
     public function __construct(Client $client)
     {
         $this->client = $client;
@@ -35,10 +27,7 @@ public function __construct(Client $client)
      *
      * @param array|SearchableEntity $searchableEntities
      *
-     * @return array
-     *
      * @throws ApiException
-     * @throws ExceptionInterface
      */
     public function index($searchableEntities): array
     {
@@ -49,7 +38,7 @@ public function index($searchableEntities): array
         $data = [];
         foreach ($searchableEntities as $entity) {
             $searchableArray = $entity->getSearchableArray();
-            if (null === $searchableArray || 0 === count($searchableArray)) {
+            if (null === $searchableArray || 0 === \count($searchableArray)) {
                 continue;
             }
 
@@ -77,10 +66,6 @@ public function index($searchableEntities): array
      * This method enables you to remove one or more objects from an index.
      *
      * @param array|SearchableEntity $searchableEntities
-     *
-     * @return array
-     *
-     * @throws ExceptionInterface
      */
     public function remove($searchableEntities): array
     {
@@ -91,7 +76,7 @@ public function remove($searchableEntities): array
         $data = [];
         foreach ($searchableEntities as $entity) {
             $searchableArray = $entity->getSearchableArray();
-            if (null === $searchableArray || 0 === count($searchableArray)) {
+            if (null === $searchableArray || 0 === \count($searchableArray)) {
                 continue;
             }
             $indexUid = $entity->getIndexName();
@@ -117,10 +102,6 @@ public function remove($searchableEntities): array
      * Clear the records of an index.
      * This method enables you to delete an index’s contents (records).
      *
-     * @param string $indexUid
-     *
-     * @return array
-     *
      * @throws ApiException
      */
     public function clear(string $indexUid): array
@@ -133,10 +114,6 @@ public function clear(string $indexUid): array
 
     /**
      * Delete an index and it's content.
-     *
-     * @param string $indexUid
-     *
-     * @return array|null
      */
     public function delete(string $indexUid): ?array
     {
@@ -145,12 +122,6 @@ public function delete(string $indexUid): ?array
 
     /**
      * Method used for querying an index.
-     *
-     * @param string $query
-     * @param string $indexUid
-     * @param array  $searchParams
-     *
-     * @return array
      */
     public function search(string $query, string $indexUid, array $searchParams): array
     {
diff --git a/src/Entity/Aggregator.php b/src/Entity/Aggregator.php
index c26138f2..73b0313b 100644
--- a/src/Entity/Aggregator.php
+++ b/src/Entity/Aggregator.php
@@ -1,13 +1,13 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Entity;
 
 use MeiliSearch\Bundle\Model\Aggregator as BaseAggregator;
 
 /**
  * Class Aggregator.
- *
- * @package MeiliSearch\Bundle\Entity
  */
 abstract class Aggregator extends BaseAggregator
 {
diff --git a/src/EventListener/MeiliSearchIndexerSubscriber.php b/src/EventListener/MeiliSearchIndexerSubscriber.php
index ecea5418..52e275b3 100644
--- a/src/EventListener/MeiliSearchIndexerSubscriber.php
+++ b/src/EventListener/MeiliSearchIndexerSubscriber.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\EventListener;
 
 use Doctrine\Common\EventSubscriber;
@@ -8,23 +10,12 @@
 
 /**
  * Class MeiliSearchIndexerSubscriber.
- *
- * @package MeiliSearch\Bundle\EventListener
  */
 final class MeiliSearchIndexerSubscriber implements EventSubscriber
 {
-    /** @var SearchService */
-    protected $searchService;
-
-    /** @var array */
-    protected $subscribedEvents;
-
-    /**
-     * MeiliSearchIndexerSubscriber constructor.
-     *
-     * @param SearchService $searchService
-     * @param array         $subscribedEvents
-     */
+    private SearchService $searchService;
+    private array $subscribedEvents;
+
     public function __construct(SearchService $searchService, array $subscribedEvents)
     {
         $this->searchService = $searchService;
@@ -48,6 +39,6 @@ public function postPersist(LifecycleEventArgs $args): void
 
     public function preRemove(LifecycleEventArgs $args): void
     {
-        $this->searchService->remove($args->getObjectManager(), $object = $args->getObject());
+        $this->searchService->remove($args->getObjectManager(), $args->getObject());
     }
 }
diff --git a/src/Exception/EntityNotFoundInObjectID.php b/src/Exception/EntityNotFoundInObjectID.php
index 9d82fdf3..fe8d4d07 100644
--- a/src/Exception/EntityNotFoundInObjectID.php
+++ b/src/Exception/EntityNotFoundInObjectID.php
@@ -1,14 +1,12 @@
 <?php
 
-namespace MeiliSearch\Bundle\Exception;
+declare(strict_types=1);
 
-use LogicException;
+namespace MeiliSearch\Bundle\Exception;
 
 /**
  * Class EntityNotFoundInObjectID.
- *
- * @package MeiliSearch\Bundle\Exception
  */
-final class EntityNotFoundInObjectID extends LogicException
+final class EntityNotFoundInObjectID extends \LogicException
 {
 }
diff --git a/src/Exception/InvalidEntityForAggregator.php b/src/Exception/InvalidEntityForAggregator.php
index bd71bbfa..8870ae5c 100644
--- a/src/Exception/InvalidEntityForAggregator.php
+++ b/src/Exception/InvalidEntityForAggregator.php
@@ -1,14 +1,12 @@
 <?php
 
-namespace MeiliSearch\Bundle\Exception;
+declare(strict_types=1);
 
-use LogicException;
+namespace MeiliSearch\Bundle\Exception;
 
 /**
  * Class InvalidEntityForAggregator.
- *
- * @package MeiliSearch\Bundle\Exception
  */
-final class InvalidEntityForAggregator extends LogicException
+final class InvalidEntityForAggregator extends \LogicException
 {
 }
diff --git a/src/Exception/InvalidSettingName.php b/src/Exception/InvalidSettingName.php
index 2f042f45..15e7b67b 100644
--- a/src/Exception/InvalidSettingName.php
+++ b/src/Exception/InvalidSettingName.php
@@ -1,14 +1,12 @@
 <?php
 
-namespace MeiliSearch\Bundle\Exception;
+declare(strict_types=1);
 
-use LogicException;
+namespace MeiliSearch\Bundle\Exception;
 
 /**
  * Class InvalidSettingName.
- *
- * @package MeiliSearch\Bundle\Exception
  */
-final class InvalidSettingName extends LogicException
+final class InvalidSettingName extends \LogicException
 {
 }
diff --git a/src/Exception/SearchHitsNotFoundException.php b/src/Exception/SearchHitsNotFoundException.php
index 1c734c99..a0a760cf 100644
--- a/src/Exception/SearchHitsNotFoundException.php
+++ b/src/Exception/SearchHitsNotFoundException.php
@@ -1,14 +1,12 @@
 <?php
 
-namespace MeiliSearch\Bundle\Exception;
+declare(strict_types=1);
 
-use LogicException;
+namespace MeiliSearch\Bundle\Exception;
 
 /**
  * Class SearchHitsNotFoundException.
- *
- * @package MeiliSearch\Bundle\Exception
  */
-final class SearchHitsNotFoundException extends LogicException
+final class SearchHitsNotFoundException extends \LogicException
 {
 }
diff --git a/src/Exception/UpdateException.php b/src/Exception/UpdateException.php
index 10e65d20..ef887f69 100644
--- a/src/Exception/UpdateException.php
+++ b/src/Exception/UpdateException.php
@@ -1,14 +1,12 @@
 <?php
 
-namespace MeiliSearch\Bundle\Exception;
+declare(strict_types=1);
 
-use LogicException;
+namespace MeiliSearch\Bundle\Exception;
 
 /**
  * Class UpdateException.
- *
- * @package MeiliSearch\Bundle\Exception
  */
-final class UpdateException extends LogicException
+final class UpdateException extends \LogicException
 {
 }
diff --git a/src/MeiliSearchBundle.php b/src/MeiliSearchBundle.php
index 908b49e7..0d1db942 100644
--- a/src/MeiliSearchBundle.php
+++ b/src/MeiliSearchBundle.php
@@ -1,13 +1,13 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle;
 
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 
 /**
  * Class MeiliSearchBundle.
- *
- * @package MeiliSearch
  */
 final class MeiliSearchBundle extends Bundle
 {
diff --git a/src/Model/Aggregator.php b/src/Model/Aggregator.php
index 6c890a98..ab090dd9 100644
--- a/src/Model/Aggregator.php
+++ b/src/Model/Aggregator.php
@@ -1,18 +1,16 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Model;
 
 use MeiliSearch\Bundle\Exception\EntityNotFoundInObjectID;
 use MeiliSearch\Bundle\Exception\InvalidEntityForAggregator;
 use Symfony\Component\Serializer\Normalizer\NormalizableInterface;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
-use function count;
-use function in_array;
 
 /**
  * Class Aggregator.
- *
- * @package MeiliSearch\Bundle\Model
  */
 abstract class Aggregator implements NormalizableInterface
 {
@@ -20,10 +18,8 @@ abstract class Aggregator implements NormalizableInterface
      * Holds the ObjectID.
      * Typically also contains information concerning the
      * entity class name, and concerning the entity id.
-     *
-     * @var string
      */
-    protected $objectID;
+    protected string $objectID;
 
     /**
      * Holds a doctrine {@ORM\Entity} or {@ODM\Document} object.
@@ -36,7 +32,6 @@ abstract class Aggregator implements NormalizableInterface
      * Aggregator constructor.
      *
      * @param object $entity
-     * @param array  $entityIdentifierValues
      */
     public function __construct($entity, array $entityIdentifierValues)
     {
@@ -46,7 +41,7 @@ public function __construct($entity, array $entityIdentifierValues)
             throw new InvalidEntityForAggregator("Aggregators don't support more than one primary key.");
         }
 
-        $this->objectID = reset($entityIdentifierValues);
+        $this->objectID = (string) reset($entityIdentifierValues);
     }
 
     /**
@@ -61,40 +56,32 @@ public static function getEntities(): array
 
     /**
      * Returns an entity id from the provided object id.
-     *
-     * @param string $objectID
-     *
-     * @return string
      */
-    public static function getEntityIdFromObjectID(string $objectID): string
+    public static function getEntityIdFromObjectId(string $objectId): string
     {
-        return $objectID;
+        return $objectId;
     }
 
     /**
      * Returns an entity class name from the provided object id.
      *
-     * @param string $objectID
-     *
-     * @return string
-     *
      * @throws EntityNotFoundInObjectID
      */
-    public static function getEntityClassFromObjectID(string $objectID)
+    public static function getEntityClassFromObjectID(string $objectId): string
     {
-        $type = explode('::', $objectID)[0];
+        $type = explode('::', $objectId)[0];
 
         if (in_array($type, static::getEntities(), true)) {
             return $type;
         }
 
-        throw new EntityNotFoundInObjectID("Entity class from ObjectID {$objectID} not found.");
+        throw new EntityNotFoundInObjectID("Entity class from ObjectID $objectId not found.");
     }
 
     /**
      * {@inheritdoc}
      */
-    public function normalize(NormalizerInterface $normalizer, $format = null, array $context = [])
+    public function normalize(NormalizerInterface $normalizer, ?string $format = null, array $context = []): array
     {
         return array_merge(['objectID' => $this->objectID], $normalizer->normalize($this->entity, $format, $context));
     }
diff --git a/src/SearchService.php b/src/SearchService.php
index 5de7b33e..3cce5bf5 100644
--- a/src/SearchService.php
+++ b/src/SearchService.php
@@ -1,80 +1,38 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle;
 
 use Doctrine\Persistence\ObjectManager;
 
 /**
  * Interface SearchService.
- *
- * @package MeiliSearch
  */
 interface SearchService
 {
     /**
      * @param string|object $className
-     *
-     * @return bool
      */
     public function isSearchable($className): bool;
 
-    /**
-     * @return array
-     */
     public function getSearchable(): array;
 
-    /**
-     * @return array
-     */
     public function getConfiguration(): array;
 
     /**
      * Get the index name for the given `$className`.
-     *
-     * @param string $className
-     *
-     * @return string
      */
     public function searchableAs(string $className): string;
 
-    /**
-     * @param ObjectManager $objectManager
-     * @param               $searchable
-     *
-     * @return array
-     */
     public function index(ObjectManager $objectManager, $searchable): array;
 
-    /**
-     * @param ObjectManager $objectManager
-     * @param               $searchable
-     *
-     * @return array
-     */
     public function remove(ObjectManager $objectManager, $searchable): array;
 
-    /**
-     * @param string $className
-     *
-     * @return array
-     */
     public function clear(string $className): array;
 
-    /**
-     * @param string $className
-     *
-     * @return array|null
-     */
     public function delete(string $className): ?array;
 
-    /**
-     * @param ObjectManager $objectManager
-     * @param string        $className
-     * @param string        $query
-     * @param array         $searchParams
-     *
-     * @return array
-     */
     public function search(
         ObjectManager $objectManager,
         string $className,
@@ -86,12 +44,6 @@ public function search(
      * Get the raw search result.
      *
      * @see https://docs.meilisearch.com/reference/api/search.html#response
-     *
-     * @param string $className
-     * @param string $query
-     * @param array  $searchParams
-     *
-     * @return array
      */
     public function rawSearch(
         string $className,
@@ -99,12 +51,5 @@ public function rawSearch(
         array $searchParams = []
     ): array;
 
-    /**
-     * @param string $className
-     * @param string $query
-     * @param array  $searchParams
-     *
-     * @return int
-     */
     public function count(string $className, string $query = '', array $searchParams = []): int;
 }
diff --git a/src/Searchable.php b/src/Searchable.php
index 704da763..5aa97185 100644
--- a/src/Searchable.php
+++ b/src/Searchable.php
@@ -1,11 +1,11 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle;
 
 /**
  * Class Searchable.
- *
- * @package MeiliSearch\Bundle
  */
 final class Searchable
 {
diff --git a/src/SearchableEntity.php b/src/SearchableEntity.php
index 58688a00..15383c0c 100644
--- a/src/SearchableEntity.php
+++ b/src/SearchableEntity.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle;
 
 use Doctrine\Persistence\Mapping\ClassMetadata;
@@ -7,41 +9,32 @@
 use Symfony\Component\Config\Definition\Exception\Exception;
 use Symfony\Component\Serializer\Exception\ExceptionInterface;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
-use function count;
 
 /**
  * Class SearchableEntity.
- *
- * @package MeiliSearch\Bundle
  */
 final class SearchableEntity
 {
-    /** @var string */
-    protected $indexUid;
+    private string $indexUid;
 
     /** @var object */
-    protected $entity;
+    private $entity;
 
-    /** @var ClassMetadata */
-    protected $entityMetadata;
+    private ClassMetadata $entityMetadata;
 
     /** @var object */
-    protected $normalizer;
+    private $normalizer;
 
-    /** @var bool */
-    protected $useSerializerGroups;
+    private bool $useSerializerGroups;
 
     /** @var int|string */
-    protected $id;
+    private $id;
 
     /**
      * SearchableEntity constructor.
      *
-     * @param string        $indexUid
-     * @param object        $entity
-     * @param ClassMetadata $entityMetadata
-     * @param object|null   $normalizer
-     * @param array         $extra
+     * @param object      $entity
+     * @param object|null $normalizer
      */
     public function __construct(
         string $indexUid,
@@ -59,17 +52,12 @@ public function __construct(
         $this->setId();
     }
 
-    /**
-     * @return string
-     */
     public function getindexUid(): string
     {
         return $this->indexUid;
     }
 
     /**
-     * @return array
-     *
      * @throws ExceptionInterface
      */
     public function getSearchableArray(): array
@@ -89,18 +77,15 @@ public function getSearchableArray(): array
         return [];
     }
 
-    /**
-     * @return void
-     */
-    private function setId()
+    private function setId(): void
     {
         $ids = $this->entityMetadata->getIdentifierValues($this->entity);
 
-        if (0 === count($ids)) {
+        if (0 === \count($ids)) {
             throw new Exception('Entity has no primary key');
         }
 
-        if (1 == count($ids)) {
+        if (1 == \count($ids)) {
             $this->id = reset($ids);
         } else {
             $objectID = '';
diff --git a/src/Services/MeiliSearchService.php b/src/Services/MeiliSearchService.php
index 400e08c7..1c21a338 100644
--- a/src/Services/MeiliSearchService.php
+++ b/src/Services/MeiliSearchService.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Services;
 
 use Doctrine\Common\Util\ClassUtils;
@@ -13,64 +15,24 @@
 use Symfony\Component\PropertyAccess\PropertyAccess;
 use Symfony\Component\PropertyAccess\PropertyAccessor;
 use Symfony\Component\Serializer\SerializerInterface;
-use function array_chunk;
-use function array_filter;
-use function array_key_exists;
-use function array_merge;
-use function array_unique;
-use function count;
-use function in_array;
-use function is_array;
-use function is_object;
-use function is_subclass_of;
 
 /**
  * Class MeiliSearchService.
- *
- * @package MeiliSearch\Bundle\Services
  */
 final class MeiliSearchService implements SearchService
 {
-    /** @var */
-    protected $normalizer;
-
-    /** @var Engine */
-    protected $engine;
-
-    /** @var array */
-    protected $configuration;
-
-    /** @var PropertyAccessor */
-    private $propertyAccessor;
-
-    /** @var array */
-    protected $searchableEntities;
-
-    /** @var array */
-    protected $entitiesAggregators;
-
-    /** @var array */
-    protected $aggregators;
-
-    /** @var array */
-    protected $classToIndexMapping;
-
-    /** @var array */
-    protected $classToSerializerGroupMapping;
-
-    /** @var array */
-    protected $indexIfMapping;
-
-    /** @var array */
-    protected $settingsMapping;
+    private SerializerInterface $normalizer;
+    private Engine $engine;
+    private array $configuration;
+    private PropertyAccessor $propertyAccessor;
+    private array $searchableEntities;
+    private array $entitiesAggregators;
+    private array $aggregators;
+    private array $classToIndexMapping;
+    private array $classToSerializerGroupMapping;
+    private array $indexIfMapping;
+    private array $settingsMapping;
 
-    /**
-     * MeiliSearchService constructor.
-     *
-     * @param SerializerInterface $normalizer
-     * @param Engine              $engine
-     * @param array               $configuration
-     */
     public function __construct(SerializerInterface $normalizer, Engine $engine, array $configuration)
     {
         $this->normalizer = $normalizer;
@@ -98,17 +60,11 @@ public function isSearchable($className): bool
         return in_array($className, $this->searchableEntities, true);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function getSearchable(): array
     {
         return $this->searchableEntities;
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function getConfiguration(): array
     {
         return $this->configuration;
@@ -122,9 +78,6 @@ public function searchableAs(string $className): string
         return $this->configuration['prefix'].$this->classToIndexMapping[$className];
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function index(ObjectManager $objectManager, $searchable): array
     {
         $searchable = is_array($searchable) ? $searchable : [$searchable];
@@ -158,9 +111,6 @@ function ($chunk) {
         );
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function remove(ObjectManager $objectManager, $searchable): array
     {
         $searchable = is_array($searchable) ? $searchable : [$searchable];
@@ -182,9 +132,6 @@ function ($chunk) {
         );
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function clear(string $className): array
     {
         $this->assertIsSearchable($className);
@@ -192,9 +139,6 @@ public function clear(string $className): array
         return $this->engine->clear($this->searchableAs($className));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function delete(string $className): ?array
     {
         $this->assertIsSearchable($className);
@@ -202,9 +146,6 @@ public function delete(string $className): ?array
         return $this->engine->delete($this->searchableAs($className));
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function search(
         ObjectManager $objectManager,
         string $className,
@@ -223,8 +164,8 @@ public function search(
 
         foreach ($ids['hits'] as $objectID) {
             if (in_array($className, $this->aggregators, true)) {
-                $entityClass = $className::getEntityClassFromObjectID($objectID);
-                $id = $className::getEntityIdFromObjectID($objectID);
+                $entityClass = $className::getEntityClassFromObjectId($objectID);
+                $id = $className::getEntityIdFromObjectId($objectID);
             } else {
                 $id = $objectID;
                 $entityClass = $className;
@@ -254,9 +195,6 @@ public function rawSearch(
         return $this->engine->search($query, $this->searchableAs($className), $searchParams);
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function count(string $className, string $query = '', array $searchParams = []): int
     {
         $this->assertIsSearchable($className);
@@ -266,8 +204,6 @@ public function count(string $className, string $query = '', array $searchParams
 
     /**
      * @param object $entity
-     *
-     * @return bool
      */
     public function shouldBeIndexed($entity): bool
     {
@@ -299,7 +235,7 @@ private function setAggregatorsAndEntitiesAggregators(): void
         $this->entitiesAggregators = [];
         $this->aggregators = [];
 
-        foreach ($this->configuration['indices'] as $name => $index) {
+        foreach ($this->configuration['indices'] as $index) {
             if (is_subclass_of($index['class'], Aggregator::class)) {
                 foreach ($index['class']::getEntities() as $entityClass) {
                     if (!isset($this->entitiesAggregators[$entityClass])) {
@@ -354,7 +290,6 @@ private function setSettingsMapping(): void
     /**
      * Returns the aggregators instances of the provided entities.
      *
-     * @param ObjectManager      $objectManager
      * @param array<int, object> $entities
      *
      * @return array<int, object>
@@ -381,11 +316,7 @@ private function getAggregatorsFromEntities(ObjectManager $objectManager, array
     /**
      * For each chunk performs the provided operation.
      *
-     * @param ObjectManager      $objectManager
      * @param array<int, object> $entities
-     * @param callable           $operation
-     *
-     * @return array
      */
     private function makeSearchServiceResponseFrom(
         ObjectManager $objectManager,
@@ -413,11 +344,6 @@ private function makeSearchServiceResponseFrom(
         return $batch;
     }
 
-    /**
-     * @param string $className
-     *
-     * @return bool
-     */
     private function canUseSerializerGroup(string $className): bool
     {
         return $this->classToSerializerGroupMapping[$className];
diff --git a/src/Services/NullSearchService.php b/src/Services/NullSearchService.php
index ac2e6b21..6d939082 100644
--- a/src/Services/NullSearchService.php
+++ b/src/Services/NullSearchService.php
@@ -1,15 +1,14 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Services;
 
 use Doctrine\Persistence\ObjectManager;
 use MeiliSearch\Bundle\SearchService;
-use stdClass;
 
 /**
  * Class NullSearchService.
- *
- * @package MeiliSearch\Bundle\Services
  */
 class NullSearchService implements SearchService
 {
@@ -21,17 +20,11 @@ public function isSearchable($className): bool
         return false;
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function getSearchable(): array
     {
         return [];
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function getConfiguration(): array
     {
         return ['batchSize' => 200];
@@ -45,48 +38,33 @@ public function searchableAs(string $className): string
         return '';
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function index(ObjectManager $objectManager, $searchable): array
     {
         return [];
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function remove(ObjectManager $objectManager, $searchable): array
     {
         return [];
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function clear(string $className): array
     {
         return [];
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function delete(string $className): ?array
     {
         return [];
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function search(
         ObjectManager $objectManager,
         string $className,
         string $query = '',
         array $searchParams = []
     ): array {
-        return [new stdClass()];
+        return [new \stdClass()];
     }
 
     /**
@@ -100,9 +78,6 @@ public function rawSearch(
         return [];
     }
 
-    /**
-     * {@inheritdoc}
-     */
     public function count(string $className, string $query = '', array $searchParams = []): int
     {
         return 0;
diff --git a/tests/BaseTest.php b/tests/BaseTest.php
index 9f83427c..f9342bc2 100644
--- a/tests/BaseTest.php
+++ b/tests/BaseTest.php
@@ -1,8 +1,9 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test;
 
-use Exception;
 use MeiliSearch\Bundle\SearchableEntity;
 use MeiliSearch\Bundle\Test\Entity\Comment;
 use MeiliSearch\Bundle\Test\Entity\Image;
@@ -12,42 +13,18 @@
 use Symfony\Component\Console\Input\ArrayInput;
 use Symfony\Component\Console\Output\ConsoleOutput;
 
-use function class_exists;
-use function getenv;
-use function is_null;
-use function rand;
-use function sprintf;
-
 /**
- * Class BaseTest
- *
- * @package MeiliSearch\Bundle
+ * Class BaseTest.
  */
 class BaseTest extends KernelTestCase
 {
-
-    public static function setUpBeforeClass(): void
-    {
-        /*
-         * Older version of PHPUnit (<6.0) load
-         * env variables differently, we override them
-         * here to make sure they're coming from the
-         * env rather than the XML config
-         */
-        if (class_exists('\PHPUnit_Runner_Version')) {
-            $_ENV['MEILISEARCH_PREFIX'] = getenv('MEILISEARCH_PREFIX');
-        }
-    }
-
-    public function setUp(): void
+    protected function setUp(): void
     {
         $this->bootKernel();
     }
 
     /**
      * @param int|string|null $id
-     *
-     * @return Post
      */
     protected function createPost($id = null): Post
     {
@@ -55,7 +32,7 @@ protected function createPost($id = null): Post
         $post->setTitle('Test');
         $post->setContent('Test content');
 
-        if (!is_null($id)) {
+        if (null !== $id) {
             $post->setId($id);
         }
 
@@ -67,7 +44,7 @@ protected function createSearchablePost(): SearchableEntity
         $post = $this->createPost(rand(100, 300));
 
         return new SearchableEntity(
-            $this->getPrefix() . 'posts',
+            $this->getPrefix().'posts',
             $post,
             $this->get('doctrine')->getManager()->getClassMetadata(Post::class),
             $this->get('serializer')
@@ -76,8 +53,6 @@ protected function createSearchablePost(): SearchableEntity
 
     /**
      * @param int|string|null $id
-     *
-     * @return Comment
      */
     protected function createComment($id = null): Comment
     {
@@ -85,7 +60,7 @@ protected function createComment($id = null): Comment
         $comment->setContent('Comment content');
         $comment->setPost(new Post(['title' => 'What a post!']));
 
-        if (!is_null($id)) {
+        if (null !== $id) {
             $comment->setId($id);
         }
 
@@ -94,14 +69,12 @@ protected function createComment($id = null): Comment
 
     /**
      * @param int|string|null $id
-     *
-     * @return Image
      */
     protected function createImage($id = null): Image
     {
         $image = new Image();
 
-        if (!is_null($id)) {
+        if (null !== $id) {
             $image->setId($id);
         }
 
@@ -113,7 +86,7 @@ protected function createSearchableImage(): SearchableEntity
         $image = $this->createImage(rand(100, 300));
 
         return new SearchableEntity(
-            $this->getPrefix() . 'image',
+            $this->getPrefix().'image',
             $image,
             $this->get('doctrine')->getManager()->getClassMetadata(Image::class),
             null
@@ -131,19 +104,17 @@ protected function get(string $id): ?object
     }
 
     /**
-     * @param Application $application
-     *
-     * @throws Exception
+     * @throws \Exception
      */
     protected function refreshDb(Application $application): void
     {
         $inputs = [
             new ArrayInput(
                 [
-                    'command'         => 'doctrine:schema:drop',
+                    'command' => 'doctrine:schema:drop',
                     '--full-database' => true,
-                    '--force'         => true,
-                    '--quiet'         => true,
+                    '--force' => true,
+                    '--quiet' => true,
                 ]
             ),
             new ArrayInput(
diff --git a/tests/Entity/Comment.php b/tests/Entity/Comment.php
index c31533a1..06be7f0c 100644
--- a/tests/Entity/Comment.php
+++ b/tests/Entity/Comment.php
@@ -1,9 +1,11 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\Entity;
 
-use DateTime;
 use Doctrine\ORM\Mapping as ORM;
+use Symfony\Component\Serializer\Annotation\Groups;
 
 /**
  * @ORM\Entity
@@ -11,21 +13,19 @@
  */
 class Comment
 {
-
     /**
-     * @var int
      * @ORM\Id
      * @ORM\GeneratedValue
-     * @ORM\Column(type="integer")
+     * @ORM\Column(type="integer", nullable=true)
+     * @Groups({"searchable"})
      */
-    private $id;
+    private ?int $id = null;
 
     /**
-     * @var Post
      * @ORM\ManyToOne(targetEntity="Post", inversedBy="comments")
      * @ORM\JoinColumn(nullable=false)
      */
-    private $post;
+    private ?Post $post = null;
 
     /**
      * @var string
@@ -35,26 +35,26 @@ class Comment
      *     max=10000,
      *     maxMessage="comment.too_long"
      * )
+     * @Groups({"searchable"})
      */
     private $content;
 
     /**
-     * @var DateTime
+     * @var \DateTime
      * @ORM\Column(type="datetime")
+     * @Groups({"searchable"})
      */
     private $publishedAt;
 
     /**
      * Comment constructor.
-     *
-     * @param array $attributes
      */
     public function __construct(array $attributes = [])
     {
-        $this->id          = $attributes['id'] ?? null;
-        $this->content     = $attributes['content'] ?? null;
-        $this->publishedAt = $attributes['publishedAt'] ?? new DateTime();
-        $this->post        = $attributes['post'] ?? null;
+        $this->id = $attributes['id'] ?? null;
+        $this->content = $attributes['content'] ?? null;
+        $this->publishedAt = $attributes['publishedAt'] ?? new \DateTime();
+        $this->post = $attributes['post'] ?? null;
     }
 
     public function getId(): ?int
@@ -81,12 +81,12 @@ public function setContent(?string $content): Comment
         return $this;
     }
 
-    public function getPublishedAt(): DateTime
+    public function getPublishedAt(): \DateTime
     {
         return $this->publishedAt;
     }
 
-    public function setPublishedAt(DateTime $publishedAt): Comment
+    public function setPublishedAt(\DateTime $publishedAt): Comment
     {
         $this->publishedAt = $publishedAt;
 
diff --git a/tests/Entity/ContentAggregator.php b/tests/Entity/ContentAggregator.php
index 751142c3..b88819ae 100644
--- a/tests/Entity/ContentAggregator.php
+++ b/tests/Entity/ContentAggregator.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\Entity;
 
 use Doctrine\ORM\Mapping as ORM;
@@ -10,11 +12,10 @@
  */
 class ContentAggregator extends Aggregator
 {
-
     public function getIsVisible(): bool
     {
         if ($this->entity instanceof Post) {
-            return $this->entity->getTitle() !== 'Foo';
+            return 'Foo' !== $this->entity->getTitle();
         }
 
         return true;
diff --git a/tests/Entity/EmptyAggregator.php b/tests/Entity/EmptyAggregator.php
index 0675d962..404d657a 100644
--- a/tests/Entity/EmptyAggregator.php
+++ b/tests/Entity/EmptyAggregator.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\Entity;
 
 use Doctrine\ORM\Mapping as ORM;
@@ -10,5 +12,4 @@
  */
 class EmptyAggregator extends Aggregator
 {
-
 }
diff --git a/tests/Entity/Image.php b/tests/Entity/Image.php
index a969dffb..2bb74830 100644
--- a/tests/Entity/Image.php
+++ b/tests/Entity/Image.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\Entity;
 
 use Doctrine\ORM\Mapping as ORM;
@@ -9,28 +11,21 @@
  */
 class Image
 {
-
     /**
-     * @var int
      * @ORM\Id
      * @ORM\GeneratedValue
      * @ORM\Column(type="integer")
      */
-    private $id;
+    private ?int $id;
 
-    /**
-     * @var string
-     */
-    private $url;
+    private string $url;
 
     /**
      * Image constructor.
-     *
-     * @param array $attributes
      */
     public function __construct(array $attributes = [])
     {
-        $this->id  = $attributes['id'] ?? null;
+        $this->id = $attributes['id'] ?? null;
         $this->url = $attributes['url'] ?? 'https://docs.meilisearch.com/logo.png';
     }
 
diff --git a/tests/Entity/Link.php b/tests/Entity/Link.php
index bc9573d2..2288f5c5 100644
--- a/tests/Entity/Link.php
+++ b/tests/Entity/Link.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\Entity;
 
 use Doctrine\ORM\Mapping as ORM;
@@ -13,34 +15,30 @@
  */
 class Link implements NormalizableInterface
 {
-
     /**
-     * @var int
      * @ORM\Id
-     * @ORM\Column(type="integer")
+     * @ORM\Column(type="integer", nullable=true)
      */
-    private $id;
+    private ?int $id = null;
 
     /**
-     * @var mixed|string $name
+     * @var mixed|string
      */
     private $name;
 
     /**
-     * @var mixed|null $url
+     * @var mixed|null
      */
     private $url;
 
     /**
      * Link constructor.
-     *
-     * @param array $attributes
      */
     public function __construct(array $attributes = [])
     {
-        $this->id   = $attributes['id'] ?? null;
+        $this->id = $attributes['id'] ?? null;
         $this->name = $attributes['name'] ?? 'This is a tag';
-        $this->url  = $attributes['url'] ?? null;
+        $this->url = $attributes['url'] ?? null;
     }
 
     private function isSponsored(): bool
@@ -49,15 +47,15 @@ private function isSponsored(): bool
     }
 
     /**
-     * @inheritDoc
+     * {@inheritDoc}
      */
     public function normalize(NormalizerInterface $normalizer, $format = null, array $context = [])
     {
         if (Searchable::NORMALIZATION_FORMAT === $format) {
             return [
-                'id'   => $this->id,
+                'id' => $this->id,
                 'name' => 'this test is correct',
-                'url'  => 'https://www.meilisearch.com',
+                'url' => 'https://www.meilisearch.com',
             ];
         }
 
diff --git a/tests/Entity/Post.php b/tests/Entity/Post.php
index 3a4fdd41..422342ab 100644
--- a/tests/Entity/Post.php
+++ b/tests/Entity/Post.php
@@ -1,9 +1,11 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\Entity;
 
-use DateTime;
 use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\Common\Collections\Collection;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Component\Serializer\Annotation\Groups;
 
@@ -13,60 +15,56 @@
  */
 class Post
 {
-
     /**
-     * @var int
      * @ORM\Id
      * @ORM\GeneratedValue
      * @ORM\Column(type="integer")
      * @Groups({"searchable"})
      * ^ Note that Groups work on private properties
      */
-    private $id;
+    private ?int $id = null;
 
     /**
-     * @var string
-     * @ORM\Column(type="string")
+     * @ORM\Column(type="string", nullable=true)
      * @Groups({"searchable"})
      * ^ Note that Groups work on private properties
      */
-    private $title;
+    private ?string $title = null;
 
     /**
-     * @var string
-     * @ORM\Column(type="text")
+     * @ORM\Column(type="text", nullable=true)
+     * @Groups({"searchable"})
      */
-    private $content;
+    private ?string $content = null;
 
     /**
-     * @var DateTime
      * @ORM\Column(type="datetime")
+     * @Groups({"searchable"})
      */
-    private $publishedAt;
+    private ?\DateTime $publishedAt = null;
 
     /**
-     * @var Comment[]|ArrayCollection
+     * @var Comment[]|Collection
      * @ORM\OneToMany(
      *      targetEntity="Comment",
      *      mappedBy="post",
      *      orphanRemoval=true
      * )
      * @ORM\OrderBy({"publishedAt": "DESC"})
+     * @Groups({"searchable"})
      */
     private $comments;
 
     /**
      * Post constructor.
-     *
-     * @param array $attributes
      */
     public function __construct(array $attributes = [])
     {
-        $this->id          = $attributes['id'] ?? null;
-        $this->title       = $attributes['title'] ?? null;
-        $this->content     = $attributes['content'] ?? null;
-        $this->publishedAt = $attributes['publishedAt'] ?? new DateTime();
-        $this->comments    = new ArrayCollection($attributes['comments'] ?? []);
+        $this->id = $attributes['id'] ?? null;
+        $this->title = $attributes['title'] ?? null;
+        $this->content = $attributes['content'] ?? null;
+        $this->publishedAt = $attributes['publishedAt'] ?? new \DateTime();
+        $this->comments = new ArrayCollection($attributes['comments'] ?? []);
     }
 
     public function getId(): ?int
@@ -111,19 +109,19 @@ public function setContent(?string $content): Post
     /**
      * @Groups({"searchable"})
      */
-    public function getPublishedAt(): ?DateTime
+    public function getPublishedAt(): ?\DateTime
     {
         return $this->publishedAt;
     }
 
-    public function setPublishedAt(?DateTime $publishedAt): Post
+    public function setPublishedAt(?\DateTime $publishedAt): Post
     {
         $this->publishedAt = $publishedAt;
 
         return $this;
     }
 
-    public function getComments(): ?ArrayCollection
+    public function getComments(): ?Collection
     {
         return $this->comments;
     }
diff --git a/tests/Entity/Tag.php b/tests/Entity/Tag.php
index 59dff4de..3461c9f5 100644
--- a/tests/Entity/Tag.php
+++ b/tests/Entity/Tag.php
@@ -1,8 +1,9 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\Entity;
 
-use DateTime;
 use Doctrine\ORM\Mapping as ORM;
 use MeiliSearch\Bundle\Searchable;
 use Symfony\Component\Serializer\Exception\ExceptionInterface;
@@ -15,38 +16,34 @@
  */
 class Tag implements NormalizableInterface
 {
-
     /**
-     * @var int
      * @ORM\Id
-     * @ORM\Column(type="integer")
+     * @ORM\Column(type="integer", nullable=true)
      */
-    private $id;
+    private ?int $id;
 
     /**
      * @ORM\Id
      * @ORM\Column(type="string")
      */
-    private $name;
+    private string $name;
 
-    private $count;
+    private int $count;
 
     private $public;
 
-    private $publishedAt;
+    private \DateTime $publishedAt;
 
     /**
      * Tag constructor.
-     *
-     * @param array $attributes
      */
     public function __construct(array $attributes = [])
     {
-        $this->id          = $attributes['id'] ?? null;
-        $this->name        = $attributes['name'] ?? 'This is a tag';
-        $this->count       = $attributes['count'] ?? 0;
-        $this->public      = $attributes['public'] ?? true;
-        $this->publishedAt = $attributes['publishedAt'] ?? new DateTime();
+        $this->id = $attributes['id'] ?? null;
+        $this->name = $attributes['name'] ?? 'This is a tag';
+        $this->count = $attributes['count'] ?? 0;
+        $this->public = $attributes['public'] ?? true;
+        $this->publishedAt = $attributes['publishedAt'] ?? new \DateTime();
     }
 
     public function isPublic(): bool
@@ -62,16 +59,17 @@ public function setPublic(bool $public): Tag
     }
 
     /**
-     * @inheritDoc
+     * {@inheritDoc}
+     *
      * @throws ExceptionInterface
      */
     public function normalize(NormalizerInterface $normalizer, $format = null, array $context = [])
     {
         if (Searchable::NORMALIZATION_FORMAT === $format) {
             return [
-                'id'          => $this->id,
-                'name'        => 'this test is correct',
-                'count'       => 10,
+                'id' => $this->id,
+                'name' => 'this test is correct',
+                'count' => 10,
                 'publishedAt' => $normalizer->normalize($this->publishedAt),
             ];
         }
diff --git a/tests/Kernel.php b/tests/Kernel.php
index e044db09..d7b07f06 100644
--- a/tests/Kernel.php
+++ b/tests/Kernel.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test;
 
 use Doctrine\Bundle\DoctrineBundle\DoctrineBundle;
@@ -9,17 +11,11 @@
 use Symfony\Component\HttpKernel\Kernel as HttpKernel;
 
 /**
- * Class Kernel
- *
- * @package MeiliSearch\Bundle
+ * Class Kernel.
  */
 class Kernel extends HttpKernel
 {
-
-    /**
-     * @inheritDoc
-     */
-    public function registerBundles()
+    public function registerBundles(): array
     {
         return [
             new FrameworkBundle(),
@@ -28,14 +24,10 @@ public function registerBundles()
         ];
     }
 
-    /**
-     * @inheritDoc
-     */
-    public function registerContainerConfiguration(LoaderInterface $loader)
+    public function registerContainerConfiguration(LoaderInterface $loader): void
     {
-        $loader->load(__DIR__ . '/config/config.yaml');
-        $loader->load(dirname(__DIR__) . '/src/Resources/config/services.xml');
-        $loader->load(__DIR__ . '/config/meili_search.yaml');
-        $loader->load(__DIR__ . '/config/services.yaml');
+        $loader->load(__DIR__.'/config/config.yaml');
+        $loader->load(__DIR__.'/../src/Resources/config/services.xml');
+        $loader->load(__DIR__.'/config/meili_search.yaml');
     }
 }
diff --git a/tests/Normalizer/CommentNormalizer.php b/tests/Normalizer/CommentNormalizer.php
index d01fbca8..a91ac814 100644
--- a/tests/Normalizer/CommentNormalizer.php
+++ b/tests/Normalizer/CommentNormalizer.php
@@ -1,33 +1,26 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\Normalizer;
 
 use MeiliSearch\Bundle\Test\Entity\Comment;
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
 /**
- * Class CommentNormalizer
- *
- * @package MeiliSearch\Bundle\Test\Normalizer
+ * Class CommentNormalizer.
  */
 class CommentNormalizer implements NormalizerInterface
 {
-
-    /**
-     * @inheritDoc
-     */
-    public function normalize($object, $format = null, array $context = [])
+    public function normalize($object, $format = null, array $context = []): array
     {
         return [
-            'content'    => $object->getContent(),
+            'content' => $object->getContent(),
             'post_title' => $object->getPost()->getTitle(),
         ];
     }
 
-    /**
-     * @inheritDoc
-     */
-    public function supportsNormalization($data, $format = null)
+    public function supportsNormalization($data, $format = null): bool
     {
         return $data instanceof Comment;
     }
diff --git a/tests/TestCase/AggregatorTest.php b/tests/TestCase/AggregatorTest.php
index 2d7e3c3c..f0ca435a 100644
--- a/tests/TestCase/AggregatorTest.php
+++ b/tests/TestCase/AggregatorTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\TestCase;
 
 use Doctrine\ORM\EntityManagerInterface;
@@ -12,13 +14,10 @@
 use Symfony\Bundle\FrameworkBundle\Console\Application;
 
 /**
- * Class AggregatorTest
- *
- * @package MeiliSearch\Bundle\Test\TestCase
+ * Class AggregatorTest.
  */
 class AggregatorTest extends BaseTest
 {
-
     /**
      * @var EntityManagerInterface
      */
@@ -58,8 +57,8 @@ public function testAggregatorProxyClass()
     {
         $post = new Post(
             [
-                'id'      => 1,
-                'title'   => 'Test',
+                'id' => 1,
+                'title' => 'Test',
                 'content' => 'Test content',
             ]
         );
@@ -69,7 +68,7 @@ public function testAggregatorProxyClass()
         $postMetadata = $this->entityManager->getClassMetadata(Post::class);
         $this->entityManager->getProxyFactory()->generateProxyClasses([$postMetadata], null);
 
-        $proxy             = $this->entityManager->getProxyFactory()->getProxy($postMetadata->getName(), ['id' => 1]);
+        $proxy = $this->entityManager->getProxyFactory()->getProxy($postMetadata->getName(), ['id' => 1]);
         $contentAggregator = new ContentAggregator($proxy, ['objectId']);
 
         $serializer = $this->get('serializer');
diff --git a/tests/TestCase/CommandsTest.php b/tests/TestCase/CommandsTest.php
index 88543215..f3efdca8 100644
--- a/tests/TestCase/CommandsTest.php
+++ b/tests/TestCase/CommandsTest.php
@@ -1,12 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\TestCase;
 
 use Doctrine\DBAL\Connection;
-use Doctrine\DBAL\DBALException;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\Persistence\ObjectManager;
-use Exception;
 use MeiliSearch\Bundle\Services\MeiliSearchService;
 use MeiliSearch\Bundle\Test\BaseTest;
 use MeiliSearch\Bundle\Test\Entity\Comment;
@@ -19,53 +19,34 @@
 use Symfony\Component\Console\Tester\CommandTester;
 
 /**
- * Class CommandsTest
- *
- * @package MeiliSearch\Bundle\Test\TestCase
+ * Class CommandsTest.
  */
 class CommandsTest extends BaseTest
 {
-
-    /** @var MeiliSearchService $searchService */
-    protected $searchService;
-
-    /** @var Client $client */
-    protected $client;
-
-    /** @var ObjectManager $objectManager */
-    protected $objectManager;
-
-    /** @var Connection $connection */
-    protected $connection;
-
-    /** @var Application $application */
-    protected $application;
-
-    /** @var string $indexName */
-    protected $indexName;
-
-    /** @var AbstractPlatform|null $platform */
-    protected $platform;
-
-    /** @var Indexes $index */
-    protected $index;
+    protected MeiliSearchService $searchService;
+    protected Client $client;
+    protected ObjectManager $objectManager;
+    protected Connection $connection;
+    protected Application $application;
+    protected string $indexName;
+    protected ?AbstractPlatform $platform;
+    protected Indexes $index;
 
     /**
-     * @inheritDoc
-     * @throws DBALException
      * @throws ApiException
-     * @throws Exception
+     * @throws \Doctrine\DBAL\Exception
+     * @throws \Exception
      */
     public function setUp(): void
     {
         parent::setUp();
         $this->searchService = $this->get('search.service');
-        $this->client        = $this->get('search.client');
+        $this->client = $this->get('search.client');
         $this->objectManager = $this->get('doctrine')->getManager();
-        $this->connection    = $this->get('doctrine')->getConnection();
-        $this->platform      = $this->connection->getDatabasePlatform();
-        $this->indexName     = 'posts';
-        $this->index         = $this->client->getOrCreateIndex($this->getPrefix() . $this->indexName);
+        $this->connection = $this->get('doctrine')->getConnection();
+        $this->platform = $this->connection->getDatabasePlatform();
+        $this->indexName = 'posts';
+        $this->index = $this->client->getOrCreateIndex($this->getPrefix().$this->indexName);
 
         $this->application = new Application(self::$kernel);
         $this->refreshDb($this->application);
@@ -86,55 +67,58 @@ public function testSearchClearUnknownIndex()
     {
         $unknownIndexName = 'test';
 
-        $command       = $this->application->find('meili:clear');
+        $command = $this->application->find('meili:clear');
         $commandTester = new CommandTester($command);
 
         $commandTester->execute(
             [
-                'command'   => $command->getName(),
+                'command' => $command->getName(),
                 '--indices' => $unknownIndexName,
             ]
         );
 
         // Checks output and ensure it failed
         $output = $commandTester->getDisplay();
-        $this->assertStringContainsString('No index named ' . $unknownIndexName, $output);
+        $this->assertStringContainsString('No index named '.$unknownIndexName, $output);
         $this->cleanUp();
     }
 
+    /**
+     * @throws \Doctrine\DBAL\Exception
+     */
     public function testSearchImportAggregator()
     {
         $now = new \DateTime();
         $this->connection->insert(
             $this->indexName,
             [
-                'title'        => 'Test',
-                'content'      => 'Test content',
+                'title' => 'Test',
+                'content' => 'Test content',
                 'published_at' => $now->format('Y-m-d H:i:s'),
             ]
         );
         $this->connection->insert(
             $this->indexName,
             [
-                'title'        => 'Test2',
-                'content'      => 'Test content2',
+                'title' => 'Test2',
+                'content' => 'Test content2',
                 'published_at' => $now->format('Y-m-d H:i:s'),
             ]
         );
         $this->connection->insert(
             $this->indexName,
             [
-                'title'        => 'Test3',
-                'content'      => 'Test content3',
+                'title' => 'Test3',
+                'content' => 'Test content3',
                 'published_at' => $now->format('Y-m-d H:i:s'),
             ]
         );
 
-        $command       = $this->application->find('meili:import');
+        $command = $this->application->find('meili:import');
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             [
-                'command'   => $command->getName(),
+                'command' => $command->getName(),
                 '--indices' => 'contents',
             ]
         );
@@ -144,7 +128,7 @@ public function testSearchImportAggregator()
         $this->assertStringContainsString('Done!', $output);
 
         // clearup table
-        $this->connection->executeUpdate($this->platform->getTruncateTableSQL($this->indexName, true));
+        $this->connection->executeStatement($this->platform->getTruncateTableSQL($this->indexName, true));
         $this->cleanUp();
     }
 }
diff --git a/tests/TestCase/ConfigurationTest.php b/tests/TestCase/ConfigurationTest.php
index 77da75e7..fd0bc936 100644
--- a/tests/TestCase/ConfigurationTest.php
+++ b/tests/TestCase/ConfigurationTest.php
@@ -1,18 +1,17 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\TestCase;
 
 use MeiliSearch\Bundle\DependencyInjection\Configuration;
 use MeiliSearch\Bundle\Test\BaseTest;
 
 /**
- * Class ConfigurationTest
- *
- * @package MeiliSearch\Bundle\Test\TestCase
+ * Class ConfigurationTest.
  */
 class ConfigurationTest extends BaseTest
 {
-
     /**
      * @dataProvider dataTestConfigurationTree
      *
@@ -23,9 +22,9 @@ public function testConfigurationTree($inputConfig, $expectedConfig)
     {
         $configuration = new Configuration();
 
-        $node             = $configuration->getConfigTreeBuilder()->buildTree();
+        $node = $configuration->getConfigTreeBuilder()->buildTree();
         $normalizedConfig = $node->normalize($inputConfig);
-        $finalizedConfig  = $node->finalize($normalizedConfig);
+        $finalizedConfig = $node->finalize($normalizedConfig);
 
         $this->assertEquals($expectedConfig, $finalizedConfig);
     }
@@ -36,60 +35,60 @@ public function dataTestConfigurationTree(): array
             'test empty config for default value' => [
                 [],
                 [
-                    'prefix'                   => null,
-                    'nbResults'                => 20,
-                    'batchSize'                => 500,
-                    'serializer'               => 'serializer',
+                    'prefix' => null,
+                    'nbResults' => 20,
+                    'batchSize' => 500,
+                    'serializer' => 'serializer',
                     'doctrineSubscribedEvents' => ['postPersist', 'postUpdate', 'preRemove'],
-                    'indices'                  => [],
+                    'indices' => [],
                 ],
             ],
-            'Simple config'                       => [
+            'Simple config' => [
                 [
-                    'prefix'    => 'sf_',
+                    'prefix' => 'sf_',
                     'nbResults' => 40,
                     'batchSize' => 100,
                 ],
                 [
-                    'prefix'                   => 'sf_',
-                    'nbResults'                => 40,
-                    'batchSize'                => 100,
-                    'serializer'               => 'serializer',
+                    'prefix' => 'sf_',
+                    'nbResults' => 40,
+                    'batchSize' => 100,
+                    'serializer' => 'serializer',
                     'doctrineSubscribedEvents' => ['postPersist', 'postUpdate', 'preRemove'],
-                    'indices'                  => [],
+                    'indices' => [],
                 ],
             ],
-            'Index config'                        => [
+            'Index config' => [
                 [
-                    'prefix'  => 'sf_',
+                    'prefix' => 'sf_',
                     'indices' => [
                         ['name' => 'posts', 'class' => 'App\Entity\Post', 'index_if' => null],
                         [
-                            'name'                     => 'tags',
-                            'class'                    => 'App\Entity\Tag',
+                            'name' => 'tags',
+                            'class' => 'App\Entity\Tag',
                             'enable_serializer_groups' => true,
-                            'index_if'                 => null
+                            'index_if' => null,
                         ],
                     ],
                 ],
                 [
-                    'prefix'                   => 'sf_',
-                    'nbResults'                => 20,
-                    'batchSize'                => 500,
-                    'serializer'               => 'serializer',
+                    'prefix' => 'sf_',
+                    'nbResults' => 20,
+                    'batchSize' => 500,
+                    'serializer' => 'serializer',
                     'doctrineSubscribedEvents' => ['postPersist', 'postUpdate', 'preRemove'],
-                    'indices'                  => [
+                    'indices' => [
                         'posts' => [
-                            'class'                    => 'App\Entity\Post',
+                            'class' => 'App\Entity\Post',
                             'enable_serializer_groups' => false,
-                            'index_if'                 => null,
-                            'settings'                 => []
+                            'index_if' => null,
+                            'settings' => [],
                         ],
-                        'tags'  => [
-                            'class'                    => 'App\Entity\Tag',
+                        'tags' => [
+                            'class' => 'App\Entity\Tag',
                             'enable_serializer_groups' => true,
-                            'index_if'                 => null,
-                            'settings'                 => []
+                            'index_if' => null,
+                            'settings' => [],
                         ],
                     ],
                 ],
diff --git a/tests/TestCase/EngineTest.php b/tests/TestCase/EngineTest.php
index ff96d274..34bc0510 100644
--- a/tests/TestCase/EngineTest.php
+++ b/tests/TestCase/EngineTest.php
@@ -1,30 +1,30 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\TestCase;
 
-use Exception;
 use MeiliSearch\Bundle\Engine;
 use MeiliSearch\Bundle\Test\BaseTest;
 use MeiliSearch\Exceptions\ApiException;
 
 /**
- * Class EngineTest
- *
- * @package MeiliSearch\Bundle\Test\TestCase
+ * Class EngineTest.
  */
 class EngineTest extends BaseTest
 {
-
-    protected $engine;
+    protected Engine $engine;
 
     public function setUp(): void
     {
         parent::setUp();
 
-        /* @var Engine */
         $this->engine = new Engine($this->get('search.client'));
     }
 
+    /**
+     * @throws ApiException
+     */
     public function testIndexingEmptyEntity()
     {
         $searchableImage = $this->createSearchableImage();
@@ -44,7 +44,7 @@ public function testIndexingEmptyEntity()
         // Search
         try {
             $this->engine->search('query', $searchableImage->getIndexUid(), []);
-        } catch (Exception $e) {
+        } catch (\Exception $e) {
             $this->assertInstanceOf(ApiException::class, $e);
         }
     }
diff --git a/tests/TestCase/SearchTest.php b/tests/TestCase/SearchTest.php
index 93a8036e..9f33ac8b 100644
--- a/tests/TestCase/SearchTest.php
+++ b/tests/TestCase/SearchTest.php
@@ -1,12 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\TestCase;
 
 use Doctrine\DBAL\Connection;
-use Doctrine\DBAL\DBALException;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 use Doctrine\Persistence\ObjectManager;
-use Exception;
 use MeiliSearch\Bundle\Services\MeiliSearchService;
 use MeiliSearch\Bundle\Test\BaseTest;
 use MeiliSearch\Bundle\Test\Entity\Comment;
@@ -19,53 +19,35 @@
 use Symfony\Component\Console\Tester\CommandTester;
 
 /**
- * Class SearchTest
- *
- * @package MeiliSearch\Bundle\Test\TestCase
+ * Class SearchTest.
  */
 class SearchTest extends BaseTest
 {
-
-    /** @var MeiliSearchService $searchService */
-    protected $searchService;
-
-    /** @var Client $client */
-    protected $client;
-
-    /** @var ObjectManager $objectManager */
-    protected $objectManager;
-
-    /** @var Connection $connection */
-    protected $connection;
-
-    /** @var Application $application */
-    protected $application;
-
-    /** @var string $indexName */
-    protected $indexName;
-
-    /** @var AbstractPlatform|null $platform */
-    protected $platform;
-
-    /** @var Indexes $index */
-    protected $index;
+    protected MeiliSearchService $searchService;
+    protected Client $client;
+    protected ObjectManager $objectManager;
+    protected Connection $connection;
+    protected Application $application;
+    protected string $indexName;
+    protected ?AbstractPlatform $platform;
+    protected Indexes $index;
 
     /**
-     * @inheritDoc
-     * @throws DBALException
+     * {@inheritDoc}
+     *
      * @throws ApiException
-     * @throws Exception
+     * @throws \Exception
      */
     public function setUp(): void
     {
         parent::setUp();
         $this->searchService = $this->get('search.service');
-        $this->client        = $this->get('search.client');
+        $this->client = $this->get('search.client');
         $this->objectManager = $this->get('doctrine')->getManager();
-        $this->connection    = $this->get('doctrine')->getConnection();
-        $this->platform      = $this->connection->getDatabasePlatform();
-        $this->indexName     = 'posts';
-        $this->index         = $this->client->getOrCreateIndex($this->getPrefix() . $this->indexName);
+        $this->connection = $this->get('doctrine')->getConnection();
+        $this->platform = $this->connection->getDatabasePlatform();
+        $this->indexName = 'posts';
+        $this->index = $this->client->getOrCreateIndex($this->getPrefix().$this->indexName);
 
         $this->application = new Application(self::$kernel);
         $this->refreshDb($this->application);
@@ -82,6 +64,9 @@ public function cleanUp()
         }
     }
 
+    /**
+     * @throws \Doctrine\DBAL\Exception
+     */
     public function testSearchImportAggregator()
     {
         $nbEntityIndexed = 0;
@@ -90,39 +75,38 @@ public function testSearchImportAggregator()
         $this->connection->insert(
             $this->indexName,
             [
-                'title'        => 'Test',
-                'content'      => 'Test content',
+                'title' => 'Test',
+                'content' => 'Test content',
                 'published_at' => $now->format('Y-m-d H:i:s'),
             ]
         );
-        $nbEntityIndexed++;
+        ++$nbEntityIndexed;
 
         $this->connection->insert(
             $this->indexName,
             [
-                'title'        => 'Test2',
-                'content'      => 'Test content2',
+                'title' => 'Test2',
+                'content' => 'Test content2',
                 'published_at' => $now->format('Y-m-d H:i:s'),
             ]
         );
-        $nbEntityIndexed++;
+        ++$nbEntityIndexed;
 
         $this->connection->insert(
             $this->indexName,
             [
-                'title'        => 'Test3',
-                'content'      => 'Test content3',
+                'title' => 'Test3',
+                'content' => 'Test content3',
                 'published_at' => $now->format('Y-m-d H:i:s'),
             ]
         );
-        $nbEntityIndexed++;
-
+        ++$nbEntityIndexed;
 
-        $command       = $this->application->find('meili:import');
+        $command = $this->application->find('meili:import');
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             [
-                'command'   => $command->getName(),
+                'command' => $command->getName(),
                 '--indices' => 'contents',
             ]
         );
@@ -135,13 +119,13 @@ public function testSearchImportAggregator()
         // Test searchService
         $searchTerm = 'test';
         $results = $this->searchService->search($this->objectManager, Post::class, $searchTerm);
-        $this->assertCount($nbEntityIndexed , $results);
+        $this->assertCount($nbEntityIndexed, $results);
 
         $results = $this->searchService->rawSearch(Post::class, $searchTerm);
-        $this->assertCount($nbEntityIndexed , $results['hits']);
+        $this->assertCount($nbEntityIndexed, $results['hits']);
 
         // clearup table
-        $this->connection->executeUpdate($this->platform->getTruncateTableSQL($this->indexName, true));
+        $this->connection->executeStatement($this->platform->getTruncateTableSQL($this->indexName, true));
         $this->cleanUp();
     }
 }
diff --git a/tests/TestCase/SerializationTest.php b/tests/TestCase/SerializationTest.php
index 4925e6d8..edfb67d3 100644
--- a/tests/TestCase/SerializationTest.php
+++ b/tests/TestCase/SerializationTest.php
@@ -1,8 +1,9 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\TestCase;
 
-use DateTime;
 use MeiliSearch\Bundle\Searchable;
 use MeiliSearch\Bundle\SearchableEntity;
 use MeiliSearch\Bundle\Test\BaseTest;
@@ -13,19 +14,16 @@
 use Symfony\Component\Serializer\Serializer;
 
 /**
- * Class SerializationTest
- *
- * @package MeiliSearch\Bundle\Test\TestCase
+ * Class SerializationTest.
  */
 class SerializationTest extends BaseTest
 {
-
     /**
      * @throws ExceptionInterface
      */
     public function testSimpleEntityToSearchableArray()
     {
-        $datetime       = new DateTime();
+        $datetime = new \DateTime();
         $dateSerializer = new Serializer([new DateTimeNormalizer()]);
         // This way we can test that DateTime's are serialized with DateTimeNormalizer
         // And not the default ObjectNormalizer
@@ -33,18 +31,18 @@ public function testSimpleEntityToSearchableArray()
 
         $post = new Post(
             [
-                'id'          => 12,
-                'title'       => 'a simple post',
-                'content'     => 'some text',
+                'id' => 12,
+                'title' => 'a simple post',
+                'content' => 'some text',
                 'publishedAt' => $datetime,
             ]
         );
         $post->addComment(
             new Comment(
                 [
-                    'content'     => 'a great comment',
+                    'content' => 'a great comment',
                     'publishedAt' => $datetime,
-                    'post'        => $post,
+                    'post' => $post,
                 ]
             )
         );
@@ -54,18 +52,20 @@ public function testSimpleEntityToSearchableArray()
             'posts',
             $post,
             $postMeta,
-            $this->get('serializer')
+            $this->get('serializer'),
+            ['useSerializerGroup' => true]
         );
 
         $expected = [
-            'id'          => 12,
-            'title'       => 'a simple post',
-            'content'     => 'some text',
+            'id' => 12,
+            'title' => 'a simple post',
+            'content' => 'some text',
             'publishedAt' => $serializedDateTime,
-            'comments'    => [
+            'comments' => [
                 [
-                    'content'    => 'a great comment',
-                    'post_title' => 'a simple post',
+                    'id' => null,
+                    'content' => 'a great comment',
+                    'publishedAt' => $serializedDateTime,
                 ],
             ],
         ];
diff --git a/tests/TestCase/SettingsTest.php b/tests/TestCase/SettingsTest.php
index a6230a8c..c43a8963 100644
--- a/tests/TestCase/SettingsTest.php
+++ b/tests/TestCase/SettingsTest.php
@@ -1,8 +1,9 @@
 <?php
 
+declare(strict_types=1);
+
 namespace MeiliSearch\Bundle\Test\TestCase;
 
-use Exception;
 use MeiliSearch\Bundle\SearchService;
 use MeiliSearch\Bundle\Test\BaseTest;
 use MeiliSearch\Client;
@@ -10,13 +11,10 @@
 use Symfony\Component\Console\Tester\CommandTester;
 
 /**
- * Class SettingsTest
- *
- * @package MeiliSearch\Bundle\Test\TestCase
+ * Class SettingsTest.
  */
 class SettingsTest extends BaseTest
 {
-
     const DEFAULT_RANKING_RULES
         = [
             'typo',
@@ -27,28 +25,21 @@ class SettingsTest extends BaseTest
             'exactness',
         ];
 
-    /** @var Client $client */
-    protected $client;
-
-    /** @var string $indexName */
-    protected $indexName;
-
-    /** @var Application $application */
-    protected $application;
-
-    /** @var SearchService $searchService */
-    protected $searchService;
+    protected Client $client;
+    protected string $indexName;
+    protected Application $application;
+    protected SearchService $searchService;
 
     /**
-     * @throws Exception
+     * @throws \Exception
      */
     public function setUp(): void
     {
         parent::setUp();
 
         $this->searchService = $this->get('search.service');
-        $this->client        = $this->get('search.client');
-        $this->indexName     = 'posts';
+        $this->client = $this->get('search.client');
+        $this->indexName = 'posts';
 
         $this->application = new Application(self::$kernel);
         $this->refreshDb($this->application);
@@ -57,8 +48,8 @@ public function setUp(): void
     public function testGetDefaultSettings()
     {
         $primaryKey = 'ObjectID';
-        $settingA   = $this->client->getOrCreateIndex('indexA')->getSettings();
-        $settingB   = $this->client->getOrCreateIndex('indexB', ['primaryKey' => $primaryKey])->getSettings();
+        $settingA = $this->client->getOrCreateIndex('indexA')->getSettings();
+        $settingB = $this->client->getOrCreateIndex('indexB', ['primaryKey' => $primaryKey])->getSettings();
 
         $this->assertEquals(self::DEFAULT_RANKING_RULES, $settingA['rankingRules']);
         $this->assertNull($settingA['distinctAttribute']);
@@ -83,13 +74,13 @@ public function testGetDefaultSettings()
 
     public function testUpdateSettings()
     {
-        $command       = $this->application->find('meili:import');
+        $command = $this->application->find('meili:import');
         $commandTester = new CommandTester($command);
         $commandTester->execute(
             [
-                'command'           => $command->getName(),
-                '--indices'         => 'posts',
-                '--update-settings' => true
+                'command' => $command->getName(),
+                '--indices' => 'posts',
+                '--update-settings' => true,
             ]
         );
 
@@ -101,5 +92,4 @@ public function testUpdateSettings()
         $this->assertNotEmpty($settings['attributesForFaceting']);
         $this->assertEquals(['title', 'publishedAt'], $settings['attributesForFaceting']);
     }
-
 }
diff --git a/tests/config/services.yaml b/tests/config/services.yaml
deleted file mode 100644
index ba863daf..00000000
--- a/tests/config/services.yaml
+++ /dev/null
@@ -1,17 +0,0 @@
-services:
-    search.search_indexer_subscriber:
-        class: MeiliSearch\Bundle\EventListener\MeiliSearchIndexerSubscriber
-        public: true
-        arguments:
-            - '@search.service'
-            # For some reason this parameter is not passed in the
-            # test environment (look at MeiliSearchExtension.php)
-            # So the service is redefined here
-            - ['postPersist', 'postUpdate', 'preRemove']
-        tags:
-            -   name: "doctrine.event_subscriber"
-            -   name: "doctrine_mongodb.odm.event_subscriber"
-
-    serializer.commentnormalizer:
-        class: MeiliSearch\Bundle\Test\Normalizer\CommentNormalizer
-        tags: [serializer.normalizer]
\ No newline at end of file