diff --git a/src/DependencyInjection/LiipTestFixturesExtension.php b/src/DependencyInjection/LiipTestFixturesExtension.php
index 687e89af..44bd5332 100644
--- a/src/DependencyInjection/LiipTestFixturesExtension.php
+++ b/src/DependencyInjection/LiipTestFixturesExtension.php
@@ -37,7 +37,7 @@ public function load(array $configs, ContainerBuilder $container): void
             // "liip_test_fixtures.cache_db.mysql"
             // instead of an array "liip_test_fixtures.cache_db"
             // with a "mysql" key.
-            if (is_array($value)) {
+            if (\is_array($value)) {
                 foreach ($value as $key2 => $value2) {
                     $container->setParameter($this->getAlias().'.'.$key.
                         '.'.$key2, $value2);
diff --git a/src/LiipTestFixturesEvents.php b/src/LiipTestFixturesEvents.php
index ab2bfc5b..51ded442 100644
--- a/src/LiipTestFixturesEvents.php
+++ b/src/LiipTestFixturesEvents.php
@@ -21,17 +21,17 @@
 final class LiipTestFixturesEvents
 {
     /** @see PreFixtureBackupRestoreEvent */
-    const PRE_FIXTURE_BACKUP_RESTORE = 'liip_test_fixtures.pre_fixture_backup_restore';
+    public const PRE_FIXTURE_BACKUP_RESTORE = 'liip_test_fixtures.pre_fixture_backup_restore';
 
     /** @see FixtureEvent */
-    const POST_FIXTURE_SETUP = 'liip_test_fixtures.post_fixture_setup';
+    public const POST_FIXTURE_SETUP = 'liip_test_fixtures.post_fixture_setup';
 
     /** @see PostFixtureBackupRestoreEvent */
-    const POST_FIXTURE_BACKUP_RESTORE = 'liip_test_fixtures.post_fixture_backup_restore';
+    public const POST_FIXTURE_BACKUP_RESTORE = 'liip_test_fixtures.post_fixture_backup_restore';
 
     /** @see ReferenceSaveEvent */
-    const PRE_REFERENCE_SAVE = 'liip_test_fixtures.pre_reference_save';
+    public const PRE_REFERENCE_SAVE = 'liip_test_fixtures.pre_reference_save';
 
     /** @see ReferenceSaveEvent */
-    const POST_REFERENCE_SAVE = 'liip_test_fixtures.post_reference_save';
+    public const POST_REFERENCE_SAVE = 'liip_test_fixtures.post_reference_save';
 }
diff --git a/src/Services/DatabaseBackup/AbstractDatabaseBackup.php b/src/Services/DatabaseBackup/AbstractDatabaseBackup.php
index ffc9a1f6..1660e720 100644
--- a/src/Services/DatabaseBackup/AbstractDatabaseBackup.php
+++ b/src/Services/DatabaseBackup/AbstractDatabaseBackup.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
diff --git a/src/Services/DatabaseBackup/DatabaseBackupInterface.php b/src/Services/DatabaseBackup/DatabaseBackupInterface.php
index 46c08f3a..abf7f08a 100644
--- a/src/Services/DatabaseBackup/DatabaseBackupInterface.php
+++ b/src/Services/DatabaseBackup/DatabaseBackupInterface.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
diff --git a/src/Services/DatabaseBackup/MongodbDatabaseBackup.php b/src/Services/DatabaseBackup/MongodbDatabaseBackup.php
index 5d44114f..2ad0e061 100644
--- a/src/Services/DatabaseBackup/MongodbDatabaseBackup.php
+++ b/src/Services/DatabaseBackup/MongodbDatabaseBackup.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
diff --git a/src/Services/DatabaseBackup/MysqlDatabaseBackup.php b/src/Services/DatabaseBackup/MysqlDatabaseBackup.php
index 02c2eb33..b9703a86 100644
--- a/src/Services/DatabaseBackup/MysqlDatabaseBackup.php
+++ b/src/Services/DatabaseBackup/MysqlDatabaseBackup.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
@@ -53,14 +55,14 @@ public function backup(AbstractExecutor $executor): void
             $params = $params['master'];
         }
 
-        $dbName = isset($params['dbname']) ? $params['dbname'] : '';
-        $dbHost = isset($params['host']) ? $params['host'] : '';
+        $dbName = $params['dbname'] ?? '';
+        $dbHost = $params['host'] ?? '';
 
         // Define parameter only if there's a value, to avoid warning from mysqldump:
         // mysqldump: [Warning] mysqldump: Empty value for 'port' specified. Will throw an error in future versions
         $port = isset($params['port']) && $params['port'] ? '--port='.$params['port'] : '';
 
-        $dbUser = isset($params['user']) ? $params['user'] : '';
+        $dbUser = $params['user'] ?? '';
         // Set password through environment variable to remove warning
         $dbPass = isset($params['password']) && $params['password'] ? 'MYSQL_PWD='.$params['password'].' ' : '';
 
@@ -82,7 +84,7 @@ public function restore(AbstractExecutor $executor, array $excludedTables = []):
         foreach ($this->metadatas as $classMetadata) {
             $tableName = $classMetadata->table['name'];
 
-            if (!in_array($tableName, $excludedTables)) {
+            if (!\in_array($tableName, $excludedTables, true)) {
                 $truncateSql[] = 'DELETE FROM '.$tableName; // in small tables it's really faster than truncate
             }
         }
@@ -121,7 +123,7 @@ protected function getReferenceBackup(): string
         return file_get_contents($this->getReferenceBackupFilePath());
     }
 
-    protected function updateSchemaIfNeed(EntityManager $em)
+    protected function updateSchemaIfNeed(EntityManager $em): void
     {
         if (!self::$schemaUpdatedFlag) {
             $schemaTool = new SchemaTool($em);
diff --git a/src/Services/DatabaseBackup/SqliteDatabaseBackup.php b/src/Services/DatabaseBackup/SqliteDatabaseBackup.php
index 4429bbb5..37b40418 100644
--- a/src/Services/DatabaseBackup/SqliteDatabaseBackup.php
+++ b/src/Services/DatabaseBackup/SqliteDatabaseBackup.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
diff --git a/src/Services/DatabaseToolCollection.php b/src/Services/DatabaseToolCollection.php
index 3c3ee1c3..d9f2eefe 100644
--- a/src/Services/DatabaseToolCollection.php
+++ b/src/Services/DatabaseToolCollection.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
diff --git a/src/Services/DatabaseTools/AbstractDatabaseTool.php b/src/Services/DatabaseTools/AbstractDatabaseTool.php
index 5ead1477..4df322c0 100644
--- a/src/Services/DatabaseTools/AbstractDatabaseTool.php
+++ b/src/Services/DatabaseTools/AbstractDatabaseTool.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
@@ -28,8 +30,8 @@
  */
 abstract class AbstractDatabaseTool
 {
-    const KEEP_DATABASE_AND_SCHEMA_PARAMETER_NAME = 'liip_test_fixtures.keep_database_and_schema';
-    const CACHE_METADATA_PARAMETER_NAME = 'liip_test_fixtures.cache_metadata';
+    public const KEEP_DATABASE_AND_SCHEMA_PARAMETER_NAME = 'liip_test_fixtures.keep_database_and_schema';
+    public const CACHE_METADATA_PARAMETER_NAME = 'liip_test_fixtures.cache_metadata';
 
     protected $container;
 
@@ -44,7 +46,7 @@ abstract class AbstractDatabaseTool
     protected $registry;
 
     /**
-     * @var null|string
+     * @var string|null
      */
     protected $omName;
 
@@ -64,7 +66,7 @@ abstract class AbstractDatabaseTool
     protected $connection;
 
     /**
-     * @var null|int
+     * @var int|null
      */
     protected $purgeMode;
 
@@ -126,7 +128,7 @@ public function getDriverName(): string
         return 'default';
     }
 
-    public function withPurgeMode(int $purgeMode): AbstractDatabaseTool
+    public function withPurgeMode(int $purgeMode): self
     {
         $newTool = clone $this;
         $newTool->setPurgeMode($purgeMode);
@@ -134,7 +136,7 @@ public function withPurgeMode(int $purgeMode): AbstractDatabaseTool
         return $newTool;
     }
 
-    public function withDatabaseCacheEnabled(bool $databaseCacheEnabled): AbstractDatabaseTool
+    public function withDatabaseCacheEnabled(bool $databaseCacheEnabled): self
     {
         $newTool = clone $this;
         $newTool->setDatabaseCacheEnabled($databaseCacheEnabled);
@@ -158,7 +160,7 @@ public function loadAllFixtures(array $groups = []): ?AbstractExecutor
             $loader = $this->container->get('test.service_container')->get('doctrine.fixtures.loader');
             $fixtures = $loader->getFixtures($groups);
             foreach ($fixtures as $fixture) {
-                $fixtureClasses[] = get_class($fixture);
+                $fixtureClasses[] = \get_class($fixture);
             }
         }
 
@@ -199,7 +201,7 @@ protected function getBackupService(): ?DatabaseBackupInterface
 
         if ($this->container->hasParameter($backupServiceParamName)) {
             $backupServiceName = $this->container->getParameter($backupServiceParamName);
-            if (is_string($backupServiceName) && $this->container->has($backupServiceName)) {
+            if (\is_string($backupServiceName) && $this->container->has($backupServiceName)) {
                 $backupService = $this->container->get($backupServiceName);
             } else {
                 @trigger_error("Could not find {$backupServiceName} in container. Possible misconfiguration.");
diff --git a/src/Services/DatabaseTools/MongoDBDatabaseTool.php b/src/Services/DatabaseTools/MongoDBDatabaseTool.php
index 5c781b2c..a5db60de 100644
--- a/src/Services/DatabaseTools/MongoDBDatabaseTool.php
+++ b/src/Services/DatabaseTools/MongoDBDatabaseTool.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
diff --git a/src/Services/DatabaseTools/ORMDatabaseTool.php b/src/Services/DatabaseTools/ORMDatabaseTool.php
index 4b59db43..7a045123 100644
--- a/src/Services/DatabaseTools/ORMDatabaseTool.php
+++ b/src/Services/DatabaseTools/ORMDatabaseTool.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
@@ -88,7 +90,7 @@ public function loadFixtures(array $classNames = [], bool $append = false): Abst
         // TODO: handle case when using persistent connections. Fail loudly?
         if (false === $this->getKeepDatabaseAndSchemaParameter()) {
             $schemaTool = new SchemaTool($this->om);
-            if (count($this->excludedDoctrineTables) > 0 || true === $append) {
+            if (\count($this->excludedDoctrineTables) > 0 || true === $append) {
                 if (!empty($this->getMetadatas())) {
                     $schemaTool->updateSchema($this->getMetadatas());
                 }
@@ -148,7 +150,7 @@ protected function createDatabaseIfNotExists(): void
         if (isset($params['master'])) {
             $params = $params['master'];
         }
-        $dbName = isset($params['dbname']) ? $params['dbname'] : '';
+        $dbName = $params['dbname'] ?? '';
 
         unset($params['dbname'], $params['url']);
 
@@ -158,7 +160,7 @@ protected function createDatabaseIfNotExists(): void
         $tmpConnection = DriverManager::getConnection($params);
         $tmpConnection->connect();
 
-        if (!in_array($dbName, $tmpConnection->getSchemaManager()->listDatabases())) {
+        if (!\in_array($dbName, $tmpConnection->getSchemaManager()->listDatabases(), true)) {
             $tmpConnection->getSchemaManager()->createDatabase($dbName);
         }
 
diff --git a/src/Services/DatabaseTools/ORMSqliteDatabaseTool.php b/src/Services/DatabaseTools/ORMSqliteDatabaseTool.php
index fabd3eaa..315b21fd 100644
--- a/src/Services/DatabaseTools/ORMSqliteDatabaseTool.php
+++ b/src/Services/DatabaseTools/ORMSqliteDatabaseTool.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
diff --git a/src/Services/DatabaseTools/PHPCRDatabaseTool.php b/src/Services/DatabaseTools/PHPCRDatabaseTool.php
index 4853afc5..0147805d 100644
--- a/src/Services/DatabaseTools/PHPCRDatabaseTool.php
+++ b/src/Services/DatabaseTools/PHPCRDatabaseTool.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
diff --git a/src/Services/FixturesLoaderFactory.php b/src/Services/FixturesLoaderFactory.php
index d92ecc65..9b9025a4 100644
--- a/src/Services/FixturesLoaderFactory.php
+++ b/src/Services/FixturesLoaderFactory.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Liip/TestFixturesBundle
  *
diff --git a/src/Services/SymfonyFixturesLoaderWrapper.php b/src/Services/SymfonyFixturesLoaderWrapper.php
index be77f155..0608e494 100644
--- a/src/Services/SymfonyFixturesLoaderWrapper.php
+++ b/src/Services/SymfonyFixturesLoaderWrapper.php
@@ -1,5 +1,16 @@
 <?php
 
+declare(strict_types=1);
+
+/*
+ * This file is part of the Liip/TestFixturesBundle
+ *
+ * (c) Lukas Kahwe Smith <smith@pooteeweet.org>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
 namespace Liip\TestFixturesBundle\Services;
 
 use Doctrine\Bundle\FixturesBundle\Loader\SymfonyFixturesLoader;
@@ -14,7 +25,7 @@ public function __construct(SymfonyFixturesLoader $symfonyFixturesLoader)
         $this->symfonyFixturesLoader = $symfonyFixturesLoader;
     }
 
-    public function loadFixturesClass($className)
+    public function loadFixturesClass($className): void
     {
         $this->addFixture($this->symfonyFixturesLoader->getFixture($className));
     }
diff --git a/tests/AppConfigEvents/EventListener/FixturesSubscriber.php b/tests/AppConfigEvents/EventListener/FixturesSubscriber.php
index 1ca6e61f..ff784af7 100644
--- a/tests/AppConfigEvents/EventListener/FixturesSubscriber.php
+++ b/tests/AppConfigEvents/EventListener/FixturesSubscriber.php
@@ -2,6 +2,15 @@
 
 declare(strict_types=1);
 
+/*
+ * This file is part of the Liip/TestFixturesBundle
+ *
+ * (c) Lukas Kahwe Smith <smith@pooteeweet.org>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
 namespace Liip\Acme\Tests\AppConfigEvents\EventListener;
 
 use Liip\TestFixturesBundle\Event\FixtureEvent;
diff --git a/tests/AppConfigPhpcr/DataFixtures/PHPCR/LoadTaskData.php b/tests/AppConfigPhpcr/DataFixtures/PHPCR/LoadTaskData.php
index e48aa145..2399849a 100644
--- a/tests/AppConfigPhpcr/DataFixtures/PHPCR/LoadTaskData.php
+++ b/tests/AppConfigPhpcr/DataFixtures/PHPCR/LoadTaskData.php
@@ -25,7 +25,7 @@ class LoadTaskData implements FixtureInterface
     public function load(ObjectManager $manager): void
     {
         if (!$manager instanceof DocumentManager) {
-            $class = get_class($manager);
+            $class = \get_class($manager);
 
             throw new RuntimeException("Fixture requires a PHPCR ODM DocumentManager instance, instance of '{$class}' given.");
         }
diff --git a/tests/Test/ConfigEventsTest.php b/tests/Test/ConfigEventsTest.php
index 97c59e2a..8f7fe0fd 100644
--- a/tests/Test/ConfigEventsTest.php
+++ b/tests/Test/ConfigEventsTest.php
@@ -37,7 +37,7 @@
  */
 class ConfigEventsTest extends KernelTestCase
 {
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
diff --git a/tests/Test/ConfigMysqlTest.php b/tests/Test/ConfigMysqlTest.php
index 4d6f77c8..fe7688c5 100644
--- a/tests/Test/ConfigMysqlTest.php
+++ b/tests/Test/ConfigMysqlTest.php
@@ -58,7 +58,7 @@ class ConfigMysqlTest extends KernelTestCase
     /** @var AbstractDatabaseTool */
     protected $databaseTool;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
@@ -71,7 +71,7 @@ public function setUp(): void
         $this->databaseTool = self::$container->get(DatabaseToolCollection::class)->get();
     }
 
-    public function testToolType()
+    public function testToolType(): void
     {
         $this->assertInstanceOf(ORMDatabaseTool::class, $this->databaseTool);
     }
@@ -219,7 +219,7 @@ public function testLoadFixturesAndExcludeFromPurge(): void
         // Check that there are 2 users.
         $this->assertSame(
             2,
-            count($this->userRepository->findAll())
+            \count($this->userRepository->findAll())
         );
 
         $this->databaseTool->setExcludedDoctrineTables(['liip_user']);
@@ -231,7 +231,7 @@ public function testLoadFixturesAndExcludeFromPurge(): void
         // The exclusion from purge worked, the user table is still alive and well.
         $this->assertSame(
             2,
-            count($this->userRepository->findAll())
+            \count($this->userRepository->findAll())
         );
     }
 
@@ -296,7 +296,7 @@ public function testLoadFixturesAndPurge(): void
         // The purge worked: there is no user.
         $this->assertSame(
             0,
-            count($this->userRepository->findAll())
+            \count($this->userRepository->findAll())
         );
     }
 
@@ -323,7 +323,7 @@ public function testLoadFixturesFiles(): void
 
         $this->assertSame(
             10,
-            count($users)
+            \count($users)
         );
 
         /** @var User $user */
diff --git a/tests/Test/ConfigPgsqlTest.php b/tests/Test/ConfigPgsqlTest.php
index 6f0198bf..b7978507 100644
--- a/tests/Test/ConfigPgsqlTest.php
+++ b/tests/Test/ConfigPgsqlTest.php
@@ -38,7 +38,7 @@
  */
 class ConfigPgsqlTest extends ConfigMysqlTest
 {
-    public function testToolType()
+    public function testToolType(): void
     {
         $this->assertInstanceOf(ORMDatabaseTool::class, $this->databaseTool);
     }
diff --git a/tests/Test/ConfigPhpcrTest.php b/tests/Test/ConfigPhpcrTest.php
index b6799352..a4513a85 100644
--- a/tests/Test/ConfigPhpcrTest.php
+++ b/tests/Test/ConfigPhpcrTest.php
@@ -41,7 +41,7 @@ class ConfigPhpcrTest extends KernelTestCase
     /** @var AbstractDatabaseTool */
     protected $databaseTool;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         if (!class_exists(DoctrinePHPCRBundle::class)) {
             $this->markTestSkipped('Need doctrine/phpcr-bundle package.');
@@ -66,7 +66,7 @@ public function setUp(): void
         $this->initRepository();
     }
 
-    public function testToolType()
+    public function testToolType(): void
     {
         $this->assertInstanceOf(PHPCRDatabaseTool::class, $this->databaseTool);
     }
diff --git a/tests/Test/ConfigSqliteTest.php b/tests/Test/ConfigSqliteTest.php
index 799905a6..46322d8f 100644
--- a/tests/Test/ConfigSqliteTest.php
+++ b/tests/Test/ConfigSqliteTest.php
@@ -46,7 +46,7 @@ class ConfigSqliteTest extends KernelTestCase
     /** @var ObjectRepository */
     private $userRepository;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
@@ -121,7 +121,7 @@ public function testLoadFixtures(): void
         // There are 2 users.
         $this->assertSame(
             2,
-            count($users)
+            \count($users)
         );
 
         /** @var User $user */
@@ -163,7 +163,7 @@ public function testLoadAll(): void
         // Using a non-existing group will result in zero users
         $this->assertSame(
             0,
-            count($users)
+            \count($users)
         );
 
         // Load the fixtures with a valid group.
@@ -186,7 +186,7 @@ public function testLoadAll(): void
         // The fixture group myGroup contains 3 users
         $this->assertSame(
             3,
-            count($users)
+            \count($users)
         );
 
         // Load all fixtures.
@@ -209,7 +209,7 @@ public function testLoadAll(): void
         // Loading all fixtures results in 12 users.
         $this->assertSame(
             12,
-            count($users)
+            \count($users)
         );
     }
 
@@ -277,7 +277,7 @@ public function testLoadDependentFixtures(): void
         // The two files with fixtures have been loaded, there are 4 users.
         $this->assertSame(
             4,
-            count($users)
+            \count($users)
         );
     }
 
@@ -300,7 +300,7 @@ public function testLoadDependentFixturesWithDependencyInjected(): void
         // The two files with fixtures have been loaded, there are 4 users.
         $this->assertSame(
             4,
-            count($users)
+            \count($users)
         );
     }
 
@@ -325,7 +325,7 @@ public function testLoadFixturesFiles(): void
 
         $this->assertSame(
             10,
-            count($users)
+            \count($users)
         );
 
         /** @var User $user */
@@ -421,7 +421,7 @@ public function testLoadFixturesFilesPaths(): void
 
         $this->assertSame(
             10,
-            count($users)
+            \count($users)
         );
 
         /** @var User $user */
@@ -459,7 +459,7 @@ public function testLoadFixturesFilesPathsWithoutLocateResource(): void
 
         $this->assertSame(
             10,
-            count($users)
+            \count($users)
         );
     }
 
diff --git a/tests/Test/ConfigTest.php b/tests/Test/ConfigTest.php
index 95a4a05b..cde9da0e 100644
--- a/tests/Test/ConfigTest.php
+++ b/tests/Test/ConfigTest.php
@@ -55,7 +55,7 @@ class ConfigTest extends KernelTestCase
     /** @var string */
     private $kernelCacheDir;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();