diff --git a/phpcs.xml.dist b/phpcs.xml.dist
index 37fe9c9..aecc899 100644
--- a/phpcs.xml.dist
+++ b/phpcs.xml.dist
@@ -21,43 +21,8 @@
         <exclude name="SlevomatCodingStandard.Namespaces.RequireOneNamespaceInFile.MoreNamespacesInFile" />
     </rule>
 
-    <!-- Deferred: long lines in test data providers -->
-    <rule ref="Generic.Files.LineLength.TooLong">
-        <exclude-pattern>tests/</exclude-pattern>
-    </rule>
-
-    <!-- Deferred: traversable/return type hints on test data providers -->
-    <rule ref="SlevomatCodingStandard.TypeHints.ReturnTypeHint.MissingTraversableTypeHintSpecification">
-        <exclude-pattern>tests/</exclude-pattern>
-    </rule>
-    <rule ref="SlevomatCodingStandard.TypeHints.ReturnTypeHint.MissingAnyTypeHint">
-        <exclude-pattern>tests/</exclude-pattern>
-    </rule>
-
     <!-- Deferred: test stubs use snake_case properties matching DB columns -->
     <rule ref="Squiz.NamingConventions.ValidVariableName.MemberNotCamelCaps">
         <exclude-pattern>tests/</exclude-pattern>
     </rule>
-
-    <!-- Deferred: test methods use snake_case for readability -->
-    <rule ref="Generic.NamingConventions.CamelCapsFunctionName.ScopeNotCamelCaps">
-        <exclude-pattern>tests/</exclude-pattern>
-    </rule>
-    <rule ref="PSR1.Methods.CamelCapsMethodName.NotCamelCaps">
-        <exclude-pattern>tests/</exclude-pattern>
-    </rule>
-
-    <!-- Deferred: test stubs lack type hints and use multi-property declarations -->
-    <rule ref="SlevomatCodingStandard.TypeHints.PropertyTypeHint.MissingAnyTypeHint">
-        <exclude-pattern>tests/</exclude-pattern>
-    </rule>
-    <rule ref="SlevomatCodingStandard.TypeHints.ParameterTypeHint.MissingAnyTypeHint">
-        <exclude-pattern>tests/</exclude-pattern>
-    </rule>
-    <rule ref="PSR2.Classes.PropertyDeclaration.Multiple">
-        <exclude-pattern>tests/</exclude-pattern>
-    </rule>
-    <rule ref="Squiz.Classes.ValidClassName.NotPascalCase">
-        <exclude-pattern>tests/</exclude-pattern>
-    </rule>
 </ruleset>
diff --git a/tests/DbTest.php b/tests/DbTest.php
index cf2dfe8..53c0581 100644
--- a/tests/DbTest.php
+++ b/tests/DbTest.php
@@ -15,7 +15,7 @@
 #[CoversClass(Db::class)]
 class DbTest extends TestCase
 {
-    protected $object;
+    protected Db $object;
 
     protected function setUp(): void
     {
@@ -53,17 +53,17 @@ public function testFetchingAll(): void
 
     public function testFetchingClass(): void
     {
-        $line = $this->object->select('*')->from('unit')->fetch('Respect\Relational\testFetchingClass');
-        $this->assertInstanceOF('Respect\Relational\testFetchingClass', $line);
+        $line = $this->object->select('*')->from('unit')->fetch('Respect\Relational\TestFetchingClass');
+        $this->assertInstanceOF('Respect\Relational\TestFetchingClass', $line);
     }
 
     public function testFetchingClassArgs(): void
     {
         $line = $this->object->select('*')->from('unit')->fetch(
-            'Respect\Relational\testFetchingClassArgs',
+            'Respect\Relational\TestFetchingClassArgs',
             ['foo'],
         );
-        $this->assertInstanceOF('Respect\Relational\testFetchingClassArgs', $line);
+        $this->assertInstanceOF('Respect\Relational\TestFetchingClassArgs', $line);
         $this->assertEquals('foo', $line->testd);
     }
 
@@ -81,7 +81,7 @@ static function ($row) {
 
     public function testFetchingInto(): void
     {
-        $x = new testFetchingInto();
+        $x = new TestFetchingInto();
         $this->object->select('*')->from('unit')->where(['testb' => 'abc'])->fetch($x);
         $this->assertEquals('abc', $x->testb);
     }
@@ -94,7 +94,8 @@ public function testRawSql(): void
 
     public function testFetchingArray(): void
     {
-        $line = $this->object->select('*')->from('unit')->where(['testb' => 'abc'])->fetch(PDO::FETCH_ASSOC);
+        $line = $this->object->select('*')->from('unit')
+            ->where(['testb' => 'abc'])->fetch(PDO::FETCH_ASSOC);
         $this->assertTrue(is_array($line));
     }
 
@@ -123,19 +124,27 @@ protected function tearDown(): void
     }
 }
 
-class testFetchingClass
+class TestFetchingClass
 {
-    public $testa, $testb, $testez;
+    public int|null $testa = null;
+
+    public string|null $testb = null;
+
+    public int|null $testez = null;
 }
 
-class testFetchingInto
+class TestFetchingInto
 {
-    public $testa, $testb, $testez;
+    public int|null $testa = null;
+
+    public string|null $testb = null;
+
+    public int|null $testez = null;
 }
 
-class testFetchingClassArgs
+class TestFetchingClassArgs
 {
-    public function __construct(public $testd)
+    public function __construct(public string|null $testd = null)
     {
     }
 }
diff --git a/tests/MapperTest.php b/tests/MapperTest.php
index fea367f..5512b15 100644
--- a/tests/MapperTest.php
+++ b/tests/MapperTest.php
@@ -31,7 +31,27 @@
 #[CoversClass(Mapper::class)]
 class MapperTest extends TestCase
 {
-    protected $conn, $mapper, $posts, $authors, $comments, $categories, $postsCategories, $issues;
+    protected PDO $conn;
+
+    protected Mapper $mapper;
+
+    /** @var list<object> */
+    protected array $posts;
+
+    /** @var list<object> */
+    protected array $authors;
+
+    /** @var list<object> */
+    protected array $comments;
+
+    /** @var list<object> */
+    protected array $categories;
+
+    /** @var list<object> */
+    protected array $postsCategories;
+
+    /** @var list<object> */
+    protected array $issues;
 
     protected function setUp(): void
     {
@@ -157,14 +177,14 @@ protected function setUp(): void
         $this->conn = $conn;
     }
 
-    public function test_creating_with_db_instance(): void
+    public function testCreatingWithDbInstance(): void
     {
         $db = new Db($this->conn);
         $mapper = new Mapper($db);
         $this->assertSame($db, $mapper->getDb());
     }
 
-    public function test_get_defined_db_instance(): void
+    public function testGetDefinedDbInstance(): void
     {
         $db = new Db($this->conn);
         $mapper = new Mapper($db);
@@ -172,13 +192,13 @@ public function test_get_defined_db_instance(): void
         $this->assertSame($db, $mapper->getDb());
     }
 
-    public function test_creating_with_invalid_args_should_throw_exception(): void
+    public function testCreatingWithInvalidArgsShouldThrowException(): void
     {
         $this->expectException(TypeError::class);
         new Mapper('foo');
     }
 
-    public function test_rolling_back_transaction(): void
+    public function testRollingBackTransaction(): void
     {
         $conn = $this->createMock(PDO::class);
         $conn->expects($this->any())
@@ -197,7 +217,7 @@ public function test_rolling_back_transaction(): void
         }
     }
 
-    public function test_ignoring_last_insert_id_errors(): void
+    public function testIgnoringLastInsertIdErrors(): void
     {
         $conn = $this->createStub(PDO::class);
         $conn->method('getAttribute')
@@ -223,7 +243,7 @@ public function test_ignoring_last_insert_id_errors(): void
         $this->assertEquals('bar', $obj->name);
     }
 
-    public function test_removing_untracked_object(): void
+    public function testRemovingUntrackedObject(): void
     {
         $comment = new stdClass();
         $comment->id = 7;
@@ -233,35 +253,35 @@ public function test_removing_untracked_object(): void
         $this->assertEmpty($this->mapper->comment[7]->fetch());
     }
 
-    public function test_fetching_single_entity_from_collection_should_return_first_record_from_table(): void
+    public function testFetchingSingleEntityFromCollectionShouldReturnFirstRecordFromTable(): void
     {
         $expectedFirstComment = reset($this->comments);
         $fetchedFirstComment = $this->mapper->comment->fetch();
         $this->assertEquals($expectedFirstComment, $fetchedFirstComment);
     }
 
-    public function test_fetching_all_entites_from_collection_should_return_all_records(): void
+    public function testFetchingAllEntitesFromCollectionShouldReturnAllRecords(): void
     {
         $expectedCategories = $this->categories;
         $fetchedCategories = $this->mapper->category->fetchAll();
         $this->assertEquals($expectedCategories, $fetchedCategories);
     }
 
-    public function test_extra_sql_on_single_fetch_should_be_applied_on_mapper_sql(): void
+    public function testExtraSqlOnSingleFetchShouldBeAppliedOnMapperSql(): void
     {
         $expectedLast = end($this->comments);
         $fetchedLast = $this->mapper->comment->fetch(Sql::orderBy('id DESC'));
         $this->assertEquals($expectedLast, $fetchedLast);
     }
 
-    public function test_extra_sql_on_fetchAll_should_be_applied_on_mapper_sql(): void
+    public function testExtraSqlOnFetchAllShouldBeAppliedOnMapperSql(): void
     {
         $expectedComments = array_reverse($this->comments);
         $fetchedComments = $this->mapper->comment->fetchAll(Sql::orderBy('id DESC'));
         $this->assertEquals($expectedComments, $fetchedComments);
     }
 
-    public function test_nested_collections_should_hydrate_results(): void
+    public function testNestedCollectionsShouldHydrateResults(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comment->post[5]->fetch();
@@ -307,7 +327,7 @@ public function testNtoN(): void
         $this->assertEquals(4, count(get_object_vars($comment->post_id)));
     }
 
-    public function testNtoNReverse(): void
+    public function testManyToManyReverse(): void
     {
         $mapper = $this->mapper;
         $cat = $mapper->category->post_category->post[5]->fetch();
@@ -321,7 +341,8 @@ public function testSimplePersist(): void
         $entity = (object) ['id' => 4, 'name' => 'inserted', 'category_id' => null];
         $mapper->category->persist($entity);
         $mapper->flush();
-        $result = $this->conn->query('select * from category where id=4')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select * from category where id=4')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals($entity, $result);
     }
 
@@ -331,7 +352,8 @@ public function testSimplePersistCollection(): void
         $entity = (object) ['id' => 4, 'name' => 'inserted', 'category_id' => null];
         $mapper->category->persist($entity);
         $mapper->flush();
-        $result = $this->conn->query('select * from category where id=4')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select * from category where id=4')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals($entity, $result);
     }
 
@@ -348,8 +370,12 @@ public function testNestedPersistCollection(): void
         ];
         $this->mapper->post->author->persist($postWithAuthor);
         $this->mapper->flush();
-        $author = $this->conn->query('select * from author order by id desc limit 1')->fetch(PDO::FETCH_OBJ);
-        $post = $this->conn->query('select * from post order by id desc limit 1')->fetch(PDO::FETCH_OBJ);
+        $author = $this->conn->query(
+            'select * from author order by id desc limit 1',
+        )->fetch(PDO::FETCH_OBJ);
+        $post = $this->conn->query(
+            'select * from post order by id desc limit 1',
+        )->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('New', $author->name);
         $this->assertEquals('hi', $post->title);
     }
@@ -368,8 +394,12 @@ public function testNestedPersistCollectionShortcut(): void
         $this->mapper->postAuthor = $this->mapper->post->author;
         $this->mapper->postAuthor->persist($postWithAuthor);
         $this->mapper->flush();
-        $author = $this->conn->query('select * from author order by id desc limit 1')->fetch(PDO::FETCH_OBJ);
-        $post = $this->conn->query('select * from post order by id desc limit 1')->fetch(PDO::FETCH_OBJ);
+        $author = $this->conn->query(
+            'select * from author order by id desc limit 1',
+        )->fetch(PDO::FETCH_OBJ);
+        $post = $this->conn->query(
+            'select * from post order by id desc limit 1',
+        )->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('New', $author->name);
         $this->assertEquals('hi', $post->title);
     }
@@ -388,8 +418,12 @@ public function testNestedPersistCollectionWithChildrenShortcut(): void
         $this->mapper->postAuthor = $this->mapper->post($this->mapper->author);
         $this->mapper->postAuthor->persist($postWithAuthor);
         $this->mapper->flush();
-        $author = $this->conn->query('select * from author order by id desc limit 1')->fetch(PDO::FETCH_OBJ);
-        $post = $this->conn->query('select * from post order by id desc limit 1')->fetch(PDO::FETCH_OBJ);
+        $author = $this->conn->query(
+            'select * from author order by id desc limit 1',
+        )->fetch(PDO::FETCH_OBJ);
+        $post = $this->conn->query(
+            'select * from post order by id desc limit 1',
+        )->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('New', $author->name);
         $this->assertEquals('hi', $post->title);
     }
@@ -400,7 +434,8 @@ public function testSubCategory(): void
         $entity = (object) ['id' => 8, 'name' => 'inserted', 'category_id' => 2];
         $mapper->category->persist($entity);
         $mapper->flush();
-        $result = $this->conn->query('select * from category where id=8')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select * from category where id=8')
+            ->fetch(PDO::FETCH_OBJ);
         $result2 = $mapper->category[8]->category->fetch();
         $this->assertEquals($result->id, $result2->id);
         $this->assertEquals($result->name, $result2->name);
@@ -413,7 +448,8 @@ public function testSubCategoryCondition(): void
         $entity = (object) ['id' => 8, 'name' => 'inserted', 'category_id' => 2];
         $mapper->category->persist($entity);
         $mapper->flush();
-        $result = $this->conn->query('select * from category where id=8')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select * from category where id=8')
+            ->fetch(PDO::FETCH_OBJ);
         $result2 = $mapper->category(['id' => 8])->category->fetch();
         $this->assertEquals($result->id, $result2->id);
         $this->assertEquals($result->name, $result2->name);
@@ -426,7 +462,9 @@ public function testAutoIncrementPersist(): void
         $entity = (object) ['id' => null, 'name' => 'inserted', 'category_id' => null];
         $mapper->category->persist($entity);
         $mapper->flush();
-        $result = $this->conn->query('select * from category where name="inserted"')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query(
+            'select * from category where name="inserted"',
+        )->fetch(PDO::FETCH_OBJ);
         $this->assertEquals($entity, $result);
         $this->assertEquals(4, $result->id);
     }
@@ -453,7 +491,8 @@ public function testPassedIdentity(): void
             ->query('select id from post where title = 12345')
             ->fetchColumn(0);
 
-        $comment = $this->conn->query('select * from comment where post_id = ' . $postId)
+        $comment = $this->conn
+            ->query('select * from comment where post_id = ' . $postId)
             ->fetchObject();
 
         $this->assertEquals('abc', $comment->text);
@@ -466,7 +505,8 @@ public function testJoinedPersist(): void
         $entity->text = 'HeyHey';
         $mapper->comment->persist($entity);
         $mapper->flush();
-        $result = $this->conn->query('select text from comment where id=8')->fetchColumn(0);
+        $result = $this->conn->query('select text from comment where id=8')
+            ->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
@@ -481,7 +521,7 @@ public function testRemove(): void
         $this->assertEquals($total, $pre - 1);
     }
 
-    public function test_fetching_entity_typed(): void
+    public function testFetchingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $mapper->entityNamespace = '\Respect\Relational\\';
@@ -489,7 +529,7 @@ public function test_fetching_entity_typed(): void
         $this->assertInstanceOf('\Respect\Relational\Comment', $comment);
     }
 
-    public function test_fetching_all_entity_typed(): void
+    public function testFetchingAllEntityTyped(): void
     {
         $mapper = $this->mapper;
         $mapper->entityNamespace = '\Respect\Relational\\';
@@ -497,7 +537,7 @@ public function test_fetching_all_entity_typed(): void
         $this->assertInstanceOf('\Respect\Relational\Comment', $comment[1]);
     }
 
-    public function test_fetching_all_entity_typed_nested(): void
+    public function testFetchingAllEntityTypedNested(): void
     {
         $mapper = $this->mapper;
         $mapper->entityNamespace = '\Respect\Relational\\';
@@ -506,7 +546,7 @@ public function test_fetching_all_entity_typed_nested(): void
         $this->assertInstanceOf('\Respect\Relational\Post', $comment[0]->post_id);
     }
 
-    public function test_persisting_entity_typed(): void
+    public function testPersistingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $mapper->entityNamespace = '\Respect\Relational\\';
@@ -514,11 +554,12 @@ public function test_persisting_entity_typed(): void
         $comment->text = 'HeyHey';
         $mapper->comment->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select text from comment where id=8')->fetchColumn(0);
+        $result = $this->conn->query('select text from comment where id=8')
+            ->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
-    public function test_persisting_new_entity_typed(): void
+    public function testPersistingNewEntityTyped(): void
     {
         $mapper = $this->mapper;
         $mapper->entityNamespace = '\Respect\Relational\\';
@@ -526,11 +567,12 @@ public function test_persisting_new_entity_typed(): void
         $comment->text = 'HeyHey';
         $mapper->comment->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select text from comment where id=9')->fetchColumn(0);
+        $result = $this->conn->query('select text from comment where id=9')
+            ->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
-    public function test_setters_and_getters_datetime_as_object(): void
+    public function testSettersAndGettersDatetimeAsObject(): void
     {
         $mapper = $this->mapper;
         $mapper->entityNamespace = '\Respect\Relational\\';
@@ -546,10 +588,16 @@ public function test_setters_and_getters_datetime_as_object(): void
         $this->assertEquals(date('Y-m-d'), $result->getDatetime()->format('Y-m-d'));
     }
 
-    public function test_style(): void
+    public function testStyle(): void
     {
-        $this->assertInstanceOf('Respect\Data\Styles\Stylable', $this->mapper->getStyle());
-        $this->assertInstanceOf('Respect\Data\Styles\Standard', $this->mapper->getStyle());
+        $this->assertInstanceOf(
+            'Respect\Data\Styles\Stylable',
+            $this->mapper->getStyle(),
+        );
+        $this->assertInstanceOf(
+            'Respect\Data\Styles\Standard',
+            $this->mapper->getStyle(),
+        );
         $styles = [
             new Styles\CakePHP(),
             new Styles\NorthWind(),
@@ -562,7 +610,7 @@ public function test_style(): void
         }
     }
 
-    public function test_feching_a_single_filtered_collection_should_not_bring_filtered_children(): void
+    public function testFetchingaSingleFilteredCollectionShouldNotBringFilteredChildren(): void
     {
         $mapper = $this->mapper;
         $mapper->authorsWithPosts = Filtered::post()->author();
@@ -570,7 +618,7 @@ public function test_feching_a_single_filtered_collection_should_not_bring_filte
         $this->assertEquals($this->authors[0], $author);
     }
 
-    public function test_persisting_a_previously_fetched_filtered_entity_back_into_its_collection(): void
+    public function testPersistingaPreviouslyFetchedFilteredEntityBackIntoItsCollection(): void
     {
         $mapper = $this->mapper;
         $mapper->authorsWithPosts = Filtered::post()->author();
@@ -578,11 +626,12 @@ public function test_persisting_a_previously_fetched_filtered_entity_back_into_i
         $author->name = 'Author Changed';
         $mapper->authorsWithPosts->persist($author);
         $mapper->flush();
-        $result = $this->conn->query('select name from author where id=1')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select name from author where id=1')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Author Changed', $result->name);
     }
 
-    public function test_persisting_a_previously_fetched_filtered_entity_back_into_a_foreign_compatible_collection(): void
+    public function testPersistingaPreviouslyFetchedFilteredEntityBackIntoaForeignCompatibleCollection(): void
     {
         $mapper = $this->mapper;
         $mapper->authorsWithPosts = Filtered::post()->author();
@@ -590,11 +639,12 @@ public function test_persisting_a_previously_fetched_filtered_entity_back_into_a
         $author->name = 'Author Changed';
         $mapper->author->persist($author);
         $mapper->flush();
-        $result = $this->conn->query('select name from author where id=1')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select name from author where id=1')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Author Changed', $result->name);
     }
 
-    public function test_persisting_a_newly_created_filtered_entity_into_its_collection(): void
+    public function testPersistingaNewlyCreatedFilteredEntityIntoItsCollection(): void
     {
         $mapper = $this->mapper;
         $mapper->authorsWithPosts = Filtered::post()->author();
@@ -603,11 +653,13 @@ public function test_persisting_a_newly_created_filtered_entity_into_its_collect
         $author->name = 'Author Changed';
         $mapper->authorsWithPosts->persist($author);
         $mapper->flush();
-        $result = $this->conn->query('select name from author order by id desc')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query(
+            'select name from author order by id desc',
+        )->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Author Changed', $result->name);
     }
 
-    public function test_persisting_a_newly_created_filtered_entity_into_a_foreig_compatible_collection(): void
+    public function testPersistingaNewlyCreatedFilteredEntityIntoaForeignCompatibleCollection(): void
     {
         $mapper = $this->mapper;
         $mapper->authorsWithPosts = Filtered::post()->author();
@@ -616,11 +668,13 @@ public function test_persisting_a_newly_created_filtered_entity_into_a_foreig_co
         $author->name = 'Author Changed';
         $mapper->author->persist($author);
         $mapper->flush();
-        $result = $this->conn->query('select name from author order by id desc')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query(
+            'select name from author order by id desc',
+        )->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Author Changed', $result->name);
     }
 
-    public function test_feching_multiple_filtered_collections_should_not_bring_filtered_children(): void
+    public function testFechingMultipleFilteredCollectionsShouldNotBringFilteredChildren(): void
     {
         $mapper = $this->mapper;
         $mapper->authorsWithPosts = Filtered::post()->author();
@@ -628,142 +682,182 @@ public function test_feching_multiple_filtered_collections_should_not_bring_filt
         $this->assertEquals($this->authors, $authors);
     }
 
-    public function test_filtered_collections_should_hydrate_non_filtered_parts_as_usual(): void
+    public function testFilteredCollectionsShouldHydrateNonFilteredPartsAsUsual(): void
     {
         $mapper = $this->mapper;
         $mapper->postsFromAuthorsWithComments = Filtered::comment()->post()->author();
         $post = $mapper->postsFromAuthorsWithComments->fetch();
-        $this->assertEquals((object) (['author_id' => $post->author_id] + (array) $this->posts[0]), $post);
+        $this->assertEquals(
+            (object) (['author_id' => $post->author_id] + (array) $this->posts[0]),
+            $post,
+        );
         $this->assertEquals($this->authors[0], $post->author_id);
     }
 
-    public function test_filtered_collections_should_persist_hydrated_non_filtered_parts_as_usual(): void
+    public function testFilteredCollectionsShouldPersistHydratedNonFilteredPartsAsUsual(): void
     {
         $mapper = $this->mapper;
         $mapper->postsFromAuthorsWithComments = Filtered::comment()->post()->author();
         $post = $mapper->postsFromAuthorsWithComments->fetch();
-        $this->assertEquals((object) (['author_id' => $post->author_id] + (array) $this->posts[0]), $post);
+        $this->assertEquals(
+            (object) (['author_id' => $post->author_id] + (array) $this->posts[0]),
+            $post,
+        );
         $this->assertEquals($this->authors[0], $post->author_id);
         $post->title = 'Title Changed';
         $post->author_id->name = 'John';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
-        $result = $this->conn->query('select name from author where id=1')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select name from author where id=1')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('John', $result->name);
     }
 
-    public function test_multiple_filtered_collections_dont_persist(): void
+    public function testMultipleFilteredCollectionsDontPersist(): void
     {
         $mapper = $this->mapper;
         $mapper->authorsWithPosts = Filtered::comment()->post->stack(Filtered::author());
         $post = $mapper->authorsWithPosts->fetch();
-        $this->assertEquals((object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'], $post);
+        $this->assertEquals(
+            (object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'],
+            $post,
+        );
         $post->title = 'Title Changed';
         $post->author_id = $mapper->author[1]->fetch();
         $post->author_id->name = 'A';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
-        $result = $this->conn->query('select name from author where id=1')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select name from author where id=1')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertNotEquals('A', $result->name);
     }
 
-    public function test_multiple_filtered_collections_dont_persist_newly_create_objects(): void
+    public function testMultipleFilteredCollectionsDontPersistNewlyCreateObjects(): void
     {
         $mapper = $this->mapper;
         $mapper->authorsWithPosts = Filtered::comment()->post->stack(Filtered::author());
         $post = $mapper->authorsWithPosts->fetch();
-        $this->assertEquals((object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'], $post);
+        $this->assertEquals(
+            (object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'],
+            $post,
+        );
         $post->title = 'Title Changed';
         $post->author_id = new stdClass();
         $post->author_id->id = null;
         $post->author_id->name = 'A';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
-        $result = $this->conn->query('select name from author order by id desc')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query(
+            'select name from author order by id desc',
+        )->fetch(PDO::FETCH_OBJ);
         $this->assertNotEquals('A', $result->name);
     }
 
-    public function test_multiple_filtered_collections_fetch_at_once_dont_persist(): void
+    public function testMultipleFilteredCollectionsFetchAtOnceDontPersist(): void
     {
         $mapper = $this->mapper;
         $mapper->authorsWithPosts = Filtered::comment()->post->stack(Filtered::author());
         $post = $mapper->authorsWithPosts->fetchAll();
         $post = $post[0];
-        $this->assertEquals((object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'], $post);
+        $this->assertEquals(
+            (object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'],
+            $post,
+        );
         $post->title = 'Title Changed';
         $post->author_id = $mapper->author[1]->fetch();
         $post->author_id->name = 'A';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
-        $result = $this->conn->query('select name from author where id=1')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select name from author where id=1')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertNotEquals('A', $result->name);
     }
 
-    public function test_reusing_registered_filtered_collections_keeps_their_filtering(): void
+    public function testReusingRegisteredFilteredCollectionsKeepsTheirFiltering(): void
     {
         $mapper = $this->mapper;
         $mapper->commentFil = Filtered::comment();
         $mapper->author = Filtered::author();
         $post = $mapper->commentFil->post->author->fetch();
-        $this->assertEquals((object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'], $post);
+        $this->assertEquals(
+            (object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'],
+            $post,
+        );
         $post->title = 'Title Changed';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
     }
 
-    public function test_reusing_registered_filtered_collections_keeps_their_filtering_on_fetchAll(): void
+    public function testReusingRegisteredFilteredCollectionsKeepsTheirFilteringOnFetchAll(): void
     {
         $mapper = $this->mapper;
         $mapper->commentFil = Filtered::comment();
         $mapper->author = Filtered::author();
         $post = $mapper->commentFil->post->author->fetchAll();
         $post = $post[0];
-        $this->assertEquals((object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'], $post);
+        $this->assertEquals(
+            (object) ['id' => '5', 'author_id' => 1, 'text' => 'Post Text', 'title' => 'Post Title'],
+            $post,
+        );
         $post->title = 'Title Changed';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
     }
 
-    public function test_registered_filtered_collections_by_column_keeps_their_filtering(): void
+    public function testRegisteredFilteredCollectionsByColumnKeepsTheirFiltering(): void
     {
         $mapper = $this->mapper;
         $mapper->post = Filtered::by('title')->post();
         $post = $mapper->post->fetch();
-        $this->assertEquals((object) ['id' => '5', 'title' => 'Post Title'], $post);
+        $this->assertEquals(
+            (object) ['id' => '5', 'title' => 'Post Title'],
+            $post,
+        );
         $post->title = 'Title Changed';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
     }
 
-    public function test_registered_filtered_collections_by_column_keeps_their_filtering_on_fetchAll(): void
+    public function testRegisteredFilteredCollectionsByColumnKeepsTheirFilteringOnFetchAll(): void
     {
         $mapper = $this->mapper;
         $mapper->post = Filtered::by('title')->post();
         $post = $mapper->post->fetchAll();
         $post = $post[0];
-        $this->assertEquals((object) ['id' => '5', 'title' => 'Post Title'], $post);
+        $this->assertEquals(
+            (object) ['id' => '5', 'title' => 'Post Title'],
+            $post,
+        );
         $post->title = 'Title Changed';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
     }
 
-    public function test_registered_filtered_wildcard_collections_keeps_their_filtering(): void
+    public function testRegisteredFilteredWildcardCollectionsKeepsTheirFiltering(): void
     {
         $mapper = $this->mapper;
         $mapper->post = Filtered::by('*')->post();
@@ -772,11 +866,12 @@ public function test_registered_filtered_wildcard_collections_keeps_their_filter
         $post->title = 'Title Changed';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
     }
 
-    public function test_registered_filtered_wildcard_collections_keeps_their_filtering_on_fetchAll(): void
+    public function testRegisteredFilteredWildcardCollectionsKeepsTheirFilteringOnFetchAll(): void
     {
         $mapper = $this->mapper;
         $mapper->post = Filtered::by('*')->post();
@@ -786,52 +881,86 @@ public function test_registered_filtered_wildcard_collections_keeps_their_filter
         $post->title = 'Title Changed';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
     }
 
-    public function test_fetching_registered_filtered_collections_alongside_normal(): void
+    public function testFetchingRegisteredFilteredCollectionsAlongsideNormal(): void
     {
         $mapper = $this->mapper;
         $mapper->post = Filtered::by('*')->post()->author();
         $post = $mapper->post->fetchAll();
         $post = $post[0];
-        $this->assertEquals((object) ['id' => '5', 'author_id' => $post->author_id], $post);
-        $this->assertEquals((object) ['name' => 'Author 1', 'id' => 1], $post->author_id);
+        $this->assertEquals(
+            (object) ['id' => '5', 'author_id' => $post->author_id],
+            $post,
+        );
+        $this->assertEquals(
+            (object) ['name' => 'Author 1', 'id' => 1],
+            $post->author_id,
+        );
         $post->title = 'Title Changed';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
     }
 
-    public function test_mixins_bring_results_from_two_tables(): void
+    public function testMixinsBringResultsFromTwoTables(): void
     {
         $mapper = $this->mapper;
         $mapper->postComment = Mix::with(['comment' => ['text']])->post()->author();
         $post = $mapper->postComment->fetch();
-        $this->assertEquals((object) ['name' => 'Author 1', 'id' => 1], $post->author_id);
-        $this->assertEquals((object) ['id' => '5', 'author_id' => $post->author_id, 'text' => 'Comment Text', 'title' => 'Post Title', 'comment_id' => 7], $post);
+        $this->assertEquals(
+            (object) ['name' => 'Author 1', 'id' => 1],
+            $post->author_id,
+        );
+        $this->assertEquals(
+            (object) [
+                'id' => '5',
+                'author_id' => $post->author_id,
+                'text' => 'Comment Text',
+                'title' => 'Post Title',
+                'comment_id' => 7,
+            ],
+            $post,
+        );
     }
 
-    public function test_mixins_persists_results_on_two_tables(): void
+    public function testMixinsPersistsResultsOnTwoTables(): void
     {
         $mapper = $this->mapper;
         $mapper->postComment = Mix::with(['comment' => ['text']])->post()->author();
         $post = $mapper->postComment->fetch();
-        $this->assertEquals((object) ['name' => 'Author 1', 'id' => 1], $post->author_id);
-        $this->assertEquals((object) ['id' => '5', 'author_id' => $post->author_id, 'text' => 'Comment Text', 'title' => 'Post Title', 'comment_id' => 7], $post);
+        $this->assertEquals(
+            (object) ['name' => 'Author 1', 'id' => 1],
+            $post->author_id,
+        );
+        $this->assertEquals(
+            (object) [
+                'id' => '5',
+                'author_id' => $post->author_id,
+                'text' => 'Comment Text',
+                'title' => 'Post Title',
+                'comment_id' => 7,
+            ],
+            $post,
+        );
         $post->title = 'Title Changed';
         $post->text = 'Comment Changed';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
-        $result = $this->conn->query('select text from comment where id=7')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select text from comment where id=7')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Comment Changed', $result->text);
     }
 
-    public function test_mixins_persists_newly_created_entities_on_two_tables(): void
+    public function testMixinsPersistsNewlyCreatedEntitiesOnTwoTables(): void
     {
         $mapper = $this->mapper;
         $mapper->postComment = Mix::with(['comment' => ['text']])->post()->author();
@@ -839,32 +968,50 @@ public function test_mixins_persists_newly_created_entities_on_two_tables(): voi
         $post->author_id = (object) ['name' => 'Author X', 'id' => null];
         $mapper->postComment->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title, text from post order by id desc')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query(
+            'select title, text from post order by id desc',
+        )->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Post X', $result->title);
         $this->assertEquals('', $result->text);
-        $result = $this->conn->query('select text from comment order by id desc')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query(
+            'select text from comment order by id desc',
+        )->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Comment X', $result->text);
     }
 
-    public function test_mixins_all(): void
+    public function testMixinsAll(): void
     {
         $mapper = $this->mapper;
         $mapper->postComment = Mix::with(['comment' => ['text']])->post()->author();
         $post = $mapper->postComment->fetchAll();
         $post = $post[0];
-        $this->assertEquals((object) ['name' => 'Author 1', 'id' => 1], $post->author_id);
-        $this->assertEquals((object) ['id' => '5', 'author_id' => $post->author_id, 'text' => 'Comment Text', 'title' => 'Post Title', 'comment_id' => 7], $post);
+        $this->assertEquals(
+            (object) ['name' => 'Author 1', 'id' => 1],
+            $post->author_id,
+        );
+        $this->assertEquals(
+            (object) [
+                'id' => '5',
+                'author_id' => $post->author_id,
+                'text' => 'Comment Text',
+                'title' => 'Post Title',
+                'comment_id' => 7,
+            ],
+            $post,
+        );
         $post->title = 'Title Changed';
         $post->text = 'Comment Changed';
         $mapper->postsFromAuthorsWithComments->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select title from post where id=5')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from post where id=5')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
-        $result = $this->conn->query('select text from comment where id=7')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select text from comment where id=7')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Comment Changed', $result->text);
     }
 
-    public function test_typed(): void
+    public function testTyped(): void
     {
         $mapper = $this->mapper;
         $mapper->entityNamespace = '\Respect\Relational\\';
@@ -877,11 +1024,12 @@ public function test_typed(): void
         $issues[0]->title = 'Title Changed';
         $mapper->typedIssues->persist($issues[0]);
         $mapper->flush();
-        $result = $this->conn->query('select title from issues where id=1')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from issues where id=1')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
     }
 
-    public function test_typed_single(): void
+    public function testTypedSingle(): void
     {
         $mapper = $this->mapper;
         $mapper->entityNamespace = '\Respect\Relational\\';
@@ -892,18 +1040,20 @@ public function test_typed_single(): void
         $issue->title = 'Title Changed';
         $mapper->typedIssues->persist($issue);
         $mapper->flush();
-        $result = $this->conn->query('select title from issues where id=1')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select title from issues where id=1')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('Title Changed', $result->title);
     }
 
-    public function test_persist_new_with_arrayobject(): void
+    public function testPersistNewWithArrayobject(): void
     {
         $mapper = $this->mapper;
         $arrayEntity = ['id' => 10, 'name' => 'array_object_category', 'category_id' => null];
         $entity = (object) $arrayEntity;
         $mapper->category->persist($entity);
         $mapper->flush();
-        $result = $this->conn->query('select * from category where id=10')->fetch(PDO::FETCH_OBJ);
+        $result = $this->conn->query('select * from category where id=10')
+            ->fetch(PDO::FETCH_OBJ);
         $this->assertEquals('array_object_category', $result->name);
     }
 
@@ -929,7 +1079,10 @@ public function testFetchingAllEntityWithoutPublicPropertiesTypedNested(): void
         $mapper->entityNamespace = '\Respect\Relational\OtherEntity\\';
         $posts = $mapper->post->author->fetchAll();
         $this->assertInstanceOf('\Respect\Relational\OtherEntity\Post', $posts[0]);
-        $this->assertInstanceOf('\Respect\Relational\OtherEntity\Author', $posts[0]->getAuthor());
+        $this->assertInstanceOf(
+            '\Respect\Relational\OtherEntity\Author',
+            $posts[0]->getAuthor(),
+        );
     }
 
     public function testPersistingEntityWithoutPublicPropertiesTyped(): void
@@ -942,7 +1095,8 @@ public function testPersistingEntityWithoutPublicPropertiesTyped(): void
 
         $mapper->post->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select text from post where id=5')->fetchColumn(0);
+        $result = $this->conn->query('select text from post where id=5')
+            ->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
@@ -961,7 +1115,8 @@ public function testPersistingNewEntityWithoutPublicPropertiesTyped(): void
         $post->setText('My new Post Text');
         $mapper->post->persist($post);
         $mapper->flush();
-        $result = $this->conn->query('select text from post where id=6')->fetchColumn(0);
+        $result = $this->conn->query('select text from post where id=6')
+            ->fetchColumn(0);
         $this->assertEquals('My new Post Text', $result);
     }
 
@@ -984,36 +1139,52 @@ public function testShouldNotExecuteEntityConstructorWhenDisabled(): void
         $mapper->entityNamespace = 'Respect\\Relational\\OtherEntity\\';
         $mapper->disableEntityConstructor = true;
 
-        $this->assertInstanceOf('Respect\\Relational\\OtherEntity\\Comment', $mapper->comment->fetch());
+        $this->assertInstanceOf(
+            'Respect\\Relational\\OtherEntity\\Comment',
+            $mapper->comment->fetch(),
+        );
     }
 }
 
 class Postcomment
 {
-    public $id = null;
+    public int|null $id = null;
 }
 
 class Bug
 {
-    public $id = null, $title, $type;
+    public int|null $id = null;
+
+    public string|null $title = null;
+
+    public string|null $type = null;
 }
+
 class Improvement
 {
-    public $id = null, $title, $type;
+    public int|null $id = null;
+
+    public string|null $title = null;
+
+    public string|null $type = null;
 }
 
 class Comment
 {
-    public $id = null, $post_id = null, $text = null;
+    public mixed $id = null;
 
-    private $datetime;
+    public mixed $post_id = null;
+
+    public string|null $text = null;
+
+    private string|null $datetime = null;
 
     public function setDatetime(Datetime $datetime): void
     {
         $this->datetime = $datetime->format('Y-m-d H:i:s');
     }
 
-    public function getDatetime()
+    public function getDatetime(): Datetime
     {
         return new Datetime($this->datetime);
     }
@@ -1021,17 +1192,23 @@ public function getDatetime()
 
 class Post
 {
-    public $id = null, $author_id = null, $text = null, $title = null;
+    public mixed $id = null;
+
+    public mixed $author_id = null;
+
+    public string|null $text = null;
+
+    public string|null $title = null;
 
     /** @Relational\isNotColumn -> annotation because generate a sql error case column not exists in db. */
-    private $datetime = '';
+    private string $datetime = '';
 
     public function setDatetime(Datetime $datetime): void
     {
         $this->datetime = $datetime->format('Y-m-d H:i:s');
     }
 
-    public function getDatetime()
+    public function getDatetime(): Datetime
     {
         return new Datetime($this->datetime);
     }
@@ -1043,34 +1220,40 @@ public function getDatetime()
 
 class Post
 {
-    private $id, $author_id, $title, $text;
+    private mixed $id = null;
 
-    public function getTitle()
+    private mixed $author_id = null;
+
+    private mixed $title = null;
+
+    private mixed $text = null;
+
+    public function getTitle(): mixed
     {
         return $this->title;
     }
 
-    public function setTitle($title): void
+    public function setTitle(mixed $title): void
     {
         $this->title = $title;
     }
 
-    public function getId()
+    public function getId(): mixed
     {
         return $this->id;
     }
 
-    public function getAuthor()
+    public function getAuthor(): mixed
     {
         return $this->author_id;
     }
 
-    public function getText()
+    public function getText(): mixed
     {
         return $this->text;
     }
 
-    public function setId($id): void
+    public function setId(mixed $id): void
     {
         $this->id = $id;
     }
@@ -1080,7 +1263,7 @@ public function setAuthor(Author $author): void
         $this->author_id = $author;
     }
 
-    public function setText($text): void
+    public function setText(mixed $text): void
     {
         $this->text = $text;
     }
@@ -1088,24 +1271,26 @@ public function setText($text): void
 
 class Author
 {
-    private $id, $name;
+    private mixed $id = null;
+
+    private mixed $name = null;
 
-    public function getId()
+    public function getId(): mixed
     {
         return $this->id;
     }
 
-    public function getName()
+    public function getName(): mixed
     {
         return $this->name;
     }
 
-    public function setId($id): void
+    public function setId(mixed $id): void
     {
         $this->id = $id;
     }
 
-    public function setName($name): void
+    public function setName(mixed $name): void
     {
         $this->name = $name;
     }
@@ -1114,13 +1299,13 @@ public function setName($name): void
 
 class Comment
 {
-    public $id = null;
+    public int|null $id = null;
 
-    public $post_id = null;
+    public int|null $post_id = null;
 
-    public $text = null;
+    public string|null $text = null;
 
-    public $datetime = null;
+    public string|null $datetime = null;
 
     public function __construct()
     {
diff --git a/tests/SqlTest.php b/tests/SqlTest.php
index bd3b4a7..8dfed0d 100644
--- a/tests/SqlTest.php
+++ b/tests/SqlTest.php
@@ -14,7 +14,7 @@
 #[CoversClass(Sql::class)]
 class SqlTest extends TestCase
 {
-    protected $object;
+    protected Sql $object;
 
     protected function setUp(): void
     {
@@ -56,14 +56,24 @@ public function testSelectTables(): void
 
     public function testSelectInnerJoin(): void
     {
-        $sql = (string) $this->object->select('*')->from('table')->innerJoin('other_table')->on('table.column = other_table.other_column');
-        $this->assertEquals('SELECT * FROM table INNER JOIN other_table ON table.column = other_table.other_column', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->innerJoin('other_table')
+            ->on('table.column = other_table.other_column');
+        $this->assertEquals(
+            'SELECT * FROM table INNER JOIN other_table ON table.column = other_table.other_column',
+            $sql,
+        );
     }
 
     public function testSelectInnerJoinArr(): void
     {
-        $sql = (string) $this->object->select('*')->from('table')->innerJoin('other_table')->on(['table.column' => 'other_table.other_column']);
-        $this->assertEquals('SELECT * FROM table INNER JOIN other_table ON table.column = other_table.other_column', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->innerJoin('other_table')
+            ->on(['table.column' => 'other_table.other_column']);
+        $this->assertEquals(
+            'SELECT * FROM table INNER JOIN other_table ON table.column = other_table.other_column',
+            $sql,
+        );
     }
 
     public function testSelectWhere(): void
@@ -90,7 +100,10 @@ public function testSelectWhereArray(): void
     {
         $data = ['column' => '123', 'other_column' => '456'];
         $sql = (string) $this->object->select('*')->from('table')->where($data);
-        $this->assertEquals('SELECT * FROM table WHERE column = ? AND other_column = ?', $sql);
+        $this->assertEquals(
+            'SELECT * FROM table WHERE column = ? AND other_column = ?',
+            $sql,
+        );
         $this->assertEquals(array_values($data), $this->object->getParams());
     }
 
@@ -98,7 +111,10 @@ public function testSelectWhereArrayEmptyAnd(): void
     {
         $data = ['column' => '123', 'other_column' => '456'];
         $sql = (string) $this->object->select('*')->from('table')->where($data)->and();
-        $this->assertEquals('SELECT * FROM table WHERE column = ? AND other_column = ?', $sql);
+        $this->assertEquals(
+            'SELECT * FROM table WHERE column = ? AND other_column = ?',
+            $sql,
+        );
         $this->assertEquals(array_values($data), $this->object->getParams());
     }
 
@@ -107,15 +123,24 @@ public function testSelectWhereOr(): void
         $data = ['column' => '123'];
         $data2 = ['other_column' => '456'];
         $sql = (string) $this->object->select('*')->from('table')->where($data)->or($data2);
-        $this->assertEquals('SELECT * FROM table WHERE column = ? OR other_column = ?', $sql);
-        $this->assertEquals(array_values(array_merge($data, $data2)), $this->object->getParams());
+        $this->assertEquals(
+            'SELECT * FROM table WHERE column = ? OR other_column = ?',
+            $sql,
+        );
+        $this->assertEquals(
+            array_values(array_merge($data, $data2)),
+            $this->object->getParams(),
+        );
     }
 
     public function testSelectWhereArrayQualifiedNames(): void
     {
         $data = ['a.column' => '123', 'b.other_column' => '456'];
         $sql = (string) $this->object->select('*')->from('table a', 'other_table b')->where($data);
-        $this->assertEquals('SELECT * FROM table a, other_table b WHERE a.column = ? AND b.other_column = ?', $sql);
+        $this->assertEquals(
+            'SELECT * FROM table a, other_table b WHERE a.column = ? AND b.other_column = ?',
+            $sql,
+        );
         $this->assertEquals(array_values($data), $this->object->getParams());
     }
 
@@ -128,8 +153,13 @@ public function testSelectGroupBy(): void
     public function testSelectGroupByHaving(): void
     {
         $condition = ['other_column' => 456, 'yet_another_column' => 567];
-        $sql = (string) $this->object->select('*')->from('table')->groupBy('column', 'other_column')->having($condition);
-        $this->assertEquals('SELECT * FROM table GROUP BY column, other_column HAVING other_column = ? AND yet_another_column = ?', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->groupBy('column', 'other_column')->having($condition);
+        $this->assertEquals(
+            'SELECT * FROM table GROUP BY column, other_column'
+            . ' HAVING other_column = ? AND yet_another_column = ?',
+            $sql,
+        );
         $this->assertEquals(array_values($condition), $this->object->getParams());
     }
 
@@ -138,8 +168,15 @@ public function testSimpleUpdate(): void
         $data = ['column' => 123, 'column_2' => 234];
         $condition = ['other_column' => 456, 'yet_another_column' => 567];
         $sql = (string) $this->object->update('table')->set($data)->where($condition);
-        $this->assertEquals('UPDATE table SET column = ?, column_2 = ? WHERE other_column = ? AND yet_another_column = ?', $sql);
-        $this->assertEquals(array_values(array_merge($data, $condition)), $this->object->getParams());
+        $this->assertEquals(
+            'UPDATE table SET column = ?, column_2 = ?'
+            . ' WHERE other_column = ? AND yet_another_column = ?',
+            $sql,
+        );
+        $this->assertEquals(
+            array_values(array_merge($data, $condition)),
+            $this->object->getParams(),
+        );
     }
 
     public function testSimpleInsert(): void
@@ -154,7 +191,10 @@ public function testSimpleDelete(): void
     {
         $condition = ['other_column' => 456, 'yet_another_column' => 567];
         $sql = (string) $this->object->deleteFrom('table')->where($condition);
-        $this->assertEquals('DELETE FROM table WHERE other_column = ? AND yet_another_column = ?', $sql);
+        $this->assertEquals(
+            'DELETE FROM table WHERE other_column = ? AND yet_another_column = ?',
+            $sql,
+        );
         $this->assertEquals(array_values($condition), $this->object->getParams());
     }
 
@@ -166,7 +206,10 @@ public function testCreateTable(): void
             'yet_another_column TEXT',
         ];
         $sql = (string) $this->object->createTable('table', $columns);
-        $this->assertEquals('CREATE TABLE table (column INT, other_column VARCHAR(255), yet_another_column TEXT)', $sql);
+        $this->assertEquals(
+            'CREATE TABLE table (column INT, other_column VARCHAR(255), yet_another_column TEXT)',
+            $sql,
+        );
     }
 
     public function testAlterTable(): void
@@ -177,7 +220,10 @@ public function testAlterTable(): void
             'ADD yet_another_column TEXT',
         ];
         $sql = (string) $this->object->alterTable('table', $columns);
-        $this->assertEquals('ALTER TABLE table ADD column INT, ADD other_column VARCHAR(255), ADD yet_another_column TEXT', $sql);
+        $this->assertEquals(
+            'ALTER TABLE table ADD column INT, ADD other_column VARCHAR(255), ADD yet_another_column TEXT',
+            $sql,
+        );
     }
 
     public function testGrant(): void
@@ -195,8 +241,12 @@ public function testRevoke(): void
     public function testComplexFunctions(): void
     {
         $condition = ["AES_DECRYPT('pass', 'salt')" => 123];
-        $sql = (string) $this->object->select('column', 'COUNT(column)', 'other_column')->from('table')->where($condition);
-        $this->assertEquals("SELECT column, COUNT(column), other_column FROM table WHERE AES_DECRYPT('pass', 'salt') = ?", $sql);
+        $sql = (string) $this->object->select('column', 'COUNT(column)', 'other_column')
+            ->from('table')->where($condition);
+        $this->assertEquals(
+            "SELECT column, COUNT(column), other_column FROM table WHERE AES_DECRYPT('pass', 'salt') = ?",
+            $sql,
+        );
         $this->assertEquals(array_values($condition), $this->object->getParams());
     }
 
@@ -205,9 +255,17 @@ public function testAggregateFunctions(): void
     {
         $where = ['abc' => 10];
         $having = ['SUM(abc) >=' => '10', 'AVG(def) =' => 15];
-        $sql = (string) $this->object->select('column', 'MAX(def)')->from('table')->where($where)->groupBy('abc', 'def')->having($having);
-        $this->assertEquals('SELECT column, MAX(def) FROM table WHERE abc = ? GROUP BY abc, def HAVING SUM(abc) >= ? AND AVG(def) = ?', $sql);
-        $this->assertEquals(array_values(array_merge($where, $having)), $this->object->getParams());
+        $sql = (string) $this->object->select('column', 'MAX(def)')->from('table')
+            ->where($where)->groupBy('abc', 'def')->having($having);
+        $this->assertEquals(
+            'SELECT column, MAX(def) FROM table WHERE abc = ?'
+            . ' GROUP BY abc, def HAVING SUM(abc) >= ? AND AVG(def) = ?',
+            $sql,
+        );
+        $this->assertEquals(
+            array_values(array_merge($where, $having)),
+            $this->object->getParams(),
+        );
     }
 
     public function testStaticBuilderCall(): void
@@ -226,7 +284,8 @@ public function testLastParameterWithoutParts(): void
         );
     }
 
-    public static function provider_sql_operators(): array
+    /** @return array<int, array<int, string>> */
+    public static function providerSqlOperators(): array
     {
         // operator, expectedWhere
         return [
@@ -243,8 +302,8 @@ public static function provider_sql_operators(): array
     }
 
     /** @ticket 13 */
-    #[DataProvider('provider_sql_operators')]
-    public function test_sql_operators($operator, $expected = null): void
+    #[DataProvider('providerSqlOperators')]
+    public function testSqlOperators(string $operator, string|null $expected = null): void
     {
         $expected = $expected ?: ' ?';
         $where    = ['id ' . $operator => 10];
@@ -279,7 +338,10 @@ public function testSetQueryWithParamsViaConstructor(): void
     public function testAppendQueryWithParams(): void
     {
         $query = 'SELECT * FROM table WHERE a > ? AND b = ?';
-        $this->object->setQuery('SELECT * FROM table WHERE a > ? AND b = ?', [1, 'foo']);
+        $this->object->setQuery(
+            'SELECT * FROM table WHERE a > ? AND b = ?',
+            [1, 'foo'],
+        );
         $sql = (string) $this->object->appendQuery('AND c = ?', [2]);
 
         $this->assertEquals($query . ' AND c = ?', $sql);
@@ -292,8 +354,12 @@ public function testSelectWhereWithRepeatedReferences(): void
         $data2 = ['a >' => 4];
         $data3 = ['b' => 'bar'];
 
-        $sql = (string) $this->object->select('*')->from('table')->where($data1)->or($data2)->and($data3);
-        $this->assertEquals('SELECT * FROM table WHERE a > ? AND b = ? OR a > ? AND b = ?', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->where($data1)->or($data2)->and($data3);
+        $this->assertEquals(
+            'SELECT * FROM table WHERE a > ? AND b = ? OR a > ? AND b = ?',
+            $sql,
+        );
         $this->assertEquals([1, 'foo', 4, 'bar'], $this->object->getParams());
     }
 
@@ -301,18 +367,31 @@ public function testSelectWhereWithConditionsGroupedByUnderscores(): void
     {
         $data = [['a' => 1], ['b' => 2], ['c' => 3], ['d' => 4]];
 
-        $sql = (string) $this->object->select('*')->from('table')->where($data[0])->and_($data[1])->or($data[2])->_();
-        $this->assertEquals('SELECT * FROM table WHERE a = ? AND (b = ? OR c = ?)', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->where($data[0])->and_($data[1])->or($data[2])->_();
+        $this->assertEquals(
+            'SELECT * FROM table WHERE a = ? AND (b = ? OR c = ?)',
+            $sql,
+        );
         $this->assertEquals([1, 2, 3], $this->object->getParams());
         $this->object->setQuery('', []);
 
-        $sql = (string) $this->object->select('*')->from('table')->where_($data[0])->or($data[1])->_()->and_($data[2])->or($data[3])->_();
-        $this->assertEquals('SELECT * FROM table WHERE (a = ? OR b = ?) AND (c = ? OR d = ?)', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->where_($data[0])->or($data[1])->_()
+            ->and_($data[2])->or($data[3])->_();
+        $this->assertEquals(
+            'SELECT * FROM table WHERE (a = ? OR b = ?) AND (c = ? OR d = ?)',
+            $sql,
+        );
         $this->assertEquals([1, 2, 3, 4], $this->object->getParams());
         $this->object->setQuery('', []);
 
-        $sql = (string) $this->object->select('*')->from('table')->where($data[0])->and_($data[1])->or_($data[2])->and($data[3])->_()->_();
-        $this->assertEquals('SELECT * FROM table WHERE a = ? AND (b = ? OR (c = ? AND d = ?))', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->where($data[0])->and_($data[1])->or_($data[2])->and($data[3])->_()->_();
+        $this->assertEquals(
+            'SELECT * FROM table WHERE a = ? AND (b = ? OR (c = ? AND d = ?))',
+            $sql,
+        );
         $this->assertEquals([1, 2, 3, 4], $this->object->getParams());
     }
 
@@ -320,53 +399,88 @@ public function testSelectWhereWithConditionsGroupedBySubqueries(): void
     {
         $data = [['a' => 1], ['b' => 2], ['c' => 3], ['d' => 4]];
 
-        $sql = (string) $this->object->select('*')->from('table')->where($data[0], Sql::cond($data[1])->or($data[2]));
-        $this->assertEquals('SELECT * FROM table WHERE a = ? AND (b = ? OR c = ?)', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->where($data[0], Sql::cond($data[1])->or($data[2]));
+        $this->assertEquals(
+            'SELECT * FROM table WHERE a = ? AND (b = ? OR c = ?)',
+            $sql,
+        );
         $this->assertEquals([1, 2, 3], $this->object->getParams());
         $this->object->setQuery('', []);
 
-        $sql = (string) $this->object->select('*')->from('table')->where(Sql::cond($data[0])->or($data[1]), Sql::cond($data[2])->or($data[3]));
-        $this->assertEquals('SELECT * FROM table WHERE (a = ? OR b = ?) AND (c = ? OR d = ?)', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->where(Sql::cond($data[0])->or($data[1]), Sql::cond($data[2])->or($data[3]));
+        $this->assertEquals(
+            'SELECT * FROM table WHERE (a = ? OR b = ?) AND (c = ? OR d = ?)',
+            $sql,
+        );
         $this->assertEquals([1, 2, 3, 4], $this->object->getParams());
         $this->object->setQuery('', []);
 
-        $sql = (string) $this->object->select('*')->from('table')->where($data[0], Sql::cond($data[1])->or(Sql::cond($data[2], $data[3])));
-        $this->assertEquals('SELECT * FROM table WHERE a = ? AND (b = ? OR (c = ? AND d = ?))', $sql);
+        $sql = (string) $this->object->select('*')->from('table')
+            ->where($data[0], Sql::cond($data[1])->or(Sql::cond($data[2], $data[3])));
+        $this->assertEquals(
+            'SELECT * FROM table WHERE a = ? AND (b = ? OR (c = ? AND d = ?))',
+            $sql,
+        );
         $this->assertEquals([1, 2, 3, 4], $this->object->getParams());
     }
 
     public function testSelectWhereWithSubquery(): void
     {
         $subquery = Sql::select('column1')->from('t2')->where(['column2' => 2]);
-        $sql = (string) $this->object->select('column1')->from('t1')->where(['column1' => $subquery, 'column2' => 'foo']);
+        $sql = (string) $this->object->select('column1')->from('t1')
+            ->where(['column1' => $subquery, 'column2' => 'foo']);
 
-        $this->assertEquals('SELECT column1 FROM t1 WHERE column1 = (SELECT column1 FROM t2 WHERE column2 = ?) AND column2 = ?', $sql);
+        $this->assertEquals(
+            'SELECT column1 FROM t1 WHERE column1 = (SELECT column1 FROM t2 WHERE column2 = ?)'
+            . ' AND column2 = ?',
+            $sql,
+        );
         $this->assertEquals([2, 'foo'], $this->object->getParams());
     }
 
     public function testSelectWhereWithNestedSubqueries(): void
     {
         $subquery1 = Sql::select('column1')->from('t3')->where(['column3' => 3]);
-        $subquery2 = Sql::select('column1')->from('t2')->where(['column2' => $subquery1, 'column3' => 'foo']);
-        $sql = (string) $this->object->select('column1')->from('t1')->where(['column1' => $subquery2]);
+        $subquery2 = Sql::select('column1')->from('t2')
+            ->where(['column2' => $subquery1, 'column3' => 'foo']);
+        $sql = (string) $this->object->select('column1')->from('t1')
+            ->where(['column1' => $subquery2]);
 
-        $this->assertEquals('SELECT column1 FROM t1 WHERE column1 = (SELECT column1 FROM t2 WHERE column2 = (SELECT column1 FROM t3 WHERE column3 = ?) AND column3 = ?)', $sql);
+        $this->assertEquals(
+            'SELECT column1 FROM t1 WHERE column1 = (SELECT column1 FROM t2'
+            . ' WHERE column2 = (SELECT column1 FROM t3 WHERE column3 = ?) AND column3 = ?)',
+            $sql,
+        );
         $this->assertEquals([3, 'foo'], $this->object->getParams());
     }
 
     public function testSelectUsingAliasedColumns(): void
     {
-        $sql = (string) $this->object->select('f1', ['alias' => 'f2'], 'f3', ['another_alias' => 'f4'])->from('table');
-        $this->assertEquals('SELECT f1, f2 AS alias, f3, f4 AS another_alias FROM table', $sql);
+        $sql = (string) $this->object->select(
+            'f1',
+            ['alias' => 'f2'],
+            'f3',
+            ['another_alias' => 'f4'],
+        )->from('table');
+        $this->assertEquals(
+            'SELECT f1, f2 AS alias, f3, f4 AS another_alias FROM table',
+            $sql,
+        );
         $this->assertEmpty($this->object->getParams());
     }
 
     public function testSelectWithColumnAsSubquery(): void
     {
         $subquery = Sql::select('f1')->from('t2')->where(['f2' => 2]);
-        $sql = (string) $this->object->select('f1', ['subalias' => $subquery])->from('t1')->where(['f2' => 'foo']);
+        $sql = (string) $this->object->select('f1', ['subalias' => $subquery])
+            ->from('t1')->where(['f2' => 'foo']);
 
-        $this->assertEquals('SELECT f1, (SELECT f1 FROM t2 WHERE f2 = ?) AS subalias FROM t1 WHERE f2 = ?', $sql);
+        $this->assertEquals(
+            'SELECT f1, (SELECT f1 FROM t2 WHERE f2 = ?) AS subalias FROM t1 WHERE f2 = ?',
+            $sql,
+        );
         $this->assertEquals([2, 'foo'], $this->object->getParams());
     }
 
@@ -374,7 +488,10 @@ public function testInsertWithValueFunctions(): void
     {
         $data = ['column' => 123, 'column_2' => 234];
         $sql = (string) $this->object->insertInto('table', $data, 'date')->values($data, 'NOW()');
-        $this->assertEquals('INSERT INTO table (column, column_2, date) VALUES (?, ?, NOW())', $sql);
+        $this->assertEquals(
+            'INSERT INTO table (column, column_2, date) VALUES (?, ?, NOW())',
+            $sql,
+        );
         $this->assertEquals(array_values($data), $this->object->getParams());
     }
 
@@ -384,7 +501,10 @@ public function testInsertWithSelectSubquery(): void
         $subquery = Sql::select('f1', 'f2')->from('t2')->where($data);
         $sql = (string) $this->object->insertInto('t1', ['f1', 'f2'])->appendQuery($subquery);
 
-        $this->assertEquals('INSERT INTO t1 (f1, f2) SELECT f1, f2 FROM t2 WHERE f3 = ? AND f4 = ?', $sql);
+        $this->assertEquals(
+            'INSERT INTO t1 (f1, f2) SELECT f1, f2 FROM t2 WHERE f3 = ? AND f4 = ?',
+            $sql,
+        );
         $this->assertEquals(array_values($data), $this->object->getParams());
     }
 }
diff --git a/tests/Styles/AbstractStyleTest.php b/tests/Styles/AbstractStyleTest.php
index f795352..d45c541 100644
--- a/tests/Styles/AbstractStyleTest.php
+++ b/tests/Styles/AbstractStyleTest.php
@@ -87,7 +87,7 @@ public static function camelCaseToSeparatorProvider(): array
     }
 
     #[DataProvider('singularPluralProvider')]
-    public function test_plural_to_singular_and_vice_versa(string $singular, string $plural): void
+    public function testPluralToSingularAndViceVersa(string $singular, string $plural): void
     {
         $pluralToSingular = new ReflectionMethod($this->style, 'pluralToSingular');
         $this->assertEquals($singular, $pluralToSingular->invoke($this->style, $plural));
@@ -97,12 +97,21 @@ public function test_plural_to_singular_and_vice_versa(string $singular, string
     }
 
     #[DataProvider('camelCaseToSeparatorProvider')]
-    public function test_camel_case_to_separator_and_vice_versa(string $separator, string $camelCase, string $separated): void
-    {
+    public function testCamelCaseToSeparatorAndViceVersa(
+        string $separator,
+        string $camelCase,
+        string $separated,
+    ): void {
         $camelCaseToSeparatorMethod = new ReflectionMethod($this->style, 'camelCaseToSeparator');
-        $this->assertEquals($separated, $camelCaseToSeparatorMethod->invoke($this->style, $camelCase, $separator));
+        $this->assertEquals(
+            $separated,
+            $camelCaseToSeparatorMethod->invoke($this->style, $camelCase, $separator),
+        );
 
         $separatorToCamelCaseMethod = new ReflectionMethod($this->style, 'separatorToCamelCase');
-        $this->assertEquals($camelCase, $separatorToCamelCaseMethod->invoke($this->style, $separated, $separator));
+        $this->assertEquals(
+            $camelCase,
+            $separatorToCamelCaseMethod->invoke($this->style, $separated, $separator),
+        );
     }
 }
diff --git a/tests/Styles/CakePHPTest.php b/tests/Styles/CakePHPTest.php
index ee5f491..4b20acf 100644
--- a/tests/Styles/CakePHPTest.php
+++ b/tests/Styles/CakePHPTest.php
@@ -22,15 +22,20 @@ class CakePHPTest extends TestCase
 
     private PDO $conn;
 
-    private $posts;
+    /** @var list<object> */
+    private array $posts;
 
-    private $authors;
+    /** @var list<object> */
+    private array $authors;
 
-    private $comments;
+    /** @var list<object> */
+    private array $comments;
 
-    private $categories;
+    /** @var list<object> */
+    private array $categories;
 
-    private $postsCategories;
+    /** @var list<object> */
+    private array $postsCategories;
 
     protected function setUp(): void
     {
@@ -162,7 +167,7 @@ protected function setUp(): void
     }
 
     #[DataProvider('tableEntityProvider')]
-    public function test_table_and_entities_methods($table, $entity): void
+    public function testTableAndEntitiesMethods(string $table, string $entity): void
     {
         $this->assertEquals($entity, $this->style->styledName($table));
         $this->assertEquals($table, $this->style->realName($entity));
@@ -170,7 +175,7 @@ public function test_table_and_entities_methods($table, $entity): void
     }
 
     #[DataProvider('columnsPropertyProvider')]
-    public function test_columns_and_properties_methods($column): void
+    public function testColumnsAndPropertiesMethods(string $column): void
     {
         $this->assertEquals($column, $this->style->styledProperty($column));
         $this->assertEquals($column, $this->style->realProperty($column));
@@ -179,27 +184,27 @@ public function test_columns_and_properties_methods($column): void
     }
 
     #[DataProvider('manyToMantTableProvider')]
-    public function test_table_from_left_right_table($left, $right, $table): void
+    public function testTableFromLeftRightTable(string $left, string $right, string $table): void
     {
         $this->assertEquals($table, $this->style->composed($left, $right));
     }
 
     #[DataProvider('foreignProvider')]
-    public function test_foreign($table, $foreign): void
+    public function testForeign(string $table, string $foreign): void
     {
         $this->assertTrue($this->style->isRemoteIdentifier($foreign));
         $this->assertEquals($table, $this->style->remoteFromIdentifier($foreign));
         $this->assertEquals($foreign, $this->style->remoteIdentifier($table));
     }
 
-    public function test_fetching_entity_typed(): void
+    public function testFetchingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comments[8]->fetch();
         $this->assertInstanceOf(__NAMESPACE__ . '\Comment', $comment);
     }
 
-    public function test_fetching_all_entity_typed(): void
+    public function testFetchingAllEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comments->fetchAll();
@@ -210,16 +215,19 @@ public function test_fetching_all_entity_typed(): void
         $this->assertInstanceOf(__NAMESPACE__ . '\Category', $categories->category_id);
     }
 
-    public function test_fetching_all_entity_typed_nested(): void
+    public function testFetchingAllEntityTypedNested(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comments->posts->authors->fetchAll();
         $this->assertInstanceOf(__NAMESPACE__ . '\Comment', $comment[0]);
         $this->assertInstanceOf(__NAMESPACE__ . '\Post', $comment[0]->post_id);
-        $this->assertInstanceOf(__NAMESPACE__ . '\Author', $comment[0]->post_id->author_id);
+        $this->assertInstanceOf(
+            __NAMESPACE__ . '\Author',
+            $comment[0]->post_id->author_id,
+        );
     }
 
-    public function test_persisting_entity_typed(): void
+    public function testPersistingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comments[8]->fetch();
@@ -227,21 +235,26 @@ public function test_persisting_entity_typed(): void
         $comment->text = 'HeyHey';
         $mapper->comments->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select text from comments where id=8')->fetchColumn(0);
+        $result = $this->conn->query(
+            'select text from comments where id=8',
+        )->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
-    public function test_persisting_new_entity_typed(): void
+    public function testPersistingNewEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = new Comment();
         $comment->text = 'HeyHey';
         $mapper->comments->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select text from comments where id=9')->fetchColumn(0);
+        $result = $this->conn->query(
+            'select text from comments where id=9',
+        )->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
+    /** @return array<int, array<int, string>> */
     public static function tableEntityProvider(): array
     {
         return [
@@ -253,6 +266,7 @@ public static function tableEntityProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function manyToMantTableProvider(): array
     {
         return [
@@ -262,6 +276,7 @@ public static function manyToMantTableProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function columnsPropertyProvider(): array
     {
         return [
@@ -273,6 +288,7 @@ public static function columnsPropertyProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function foreignProvider(): array
     {
         return [
@@ -286,21 +302,45 @@ public static function foreignProvider(): array
 
 class Post
 {
-    public $id, $title, $text, $author_id;
+    public mixed $id = null;
+
+    public string|null $title = null;
+
+    public string|null $text = null;
+
+    public mixed $author_id = null;
 }
+
 class Author
 {
-    public $id, $name;
+    public mixed $id = null;
+
+    public string|null $name = null;
 }
+
 class Comment
 {
-    public $id, $post_id, $text;
+    public mixed $id = null;
+
+    public mixed $post_id = null;
+
+    public string|null $text = null;
 }
+
 class Category
 {
-    public $id, $name, $category_id;
+    public mixed $id = null;
+
+    public string|null $name = null;
+
+    public mixed $category_id = null;
 }
+
 class PostCategory
 {
-    public $id, $post_id, $category_id;
+    public mixed $id = null;
+
+    public mixed $post_id = null;
+
+    public mixed $category_id = null;
 }
diff --git a/tests/Styles/NorthWindTest.php b/tests/Styles/NorthWindTest.php
index 99c52cd..f26f26b 100644
--- a/tests/Styles/NorthWindTest.php
+++ b/tests/Styles/NorthWindTest.php
@@ -22,15 +22,20 @@ class NorthWindTest extends TestCase
 
     private PDO $conn;
 
-    private $posts;
+    /** @var list<object> */
+    private array $posts;
 
-    private $authors;
+    /** @var list<object> */
+    private array $authors;
 
-    private $comments;
+    /** @var list<object> */
+    private array $comments;
 
-    private $categories;
+    /** @var list<object> */
+    private array $categories;
 
-    private $postsCategories;
+    /** @var list<object> */
+    private array $postsCategories;
 
     protected function setUp(): void
     {
@@ -160,6 +165,7 @@ protected function setUp(): void
         $this->mapper->entityNamespace = __NAMESPACE__ . '\\';
     }
 
+    /** @return array<int, array<int, string>> */
     public static function tableEntityProvider(): array
     {
         return [
@@ -171,6 +177,7 @@ public static function tableEntityProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function manyToMantTableProvider(): array
     {
         return [
@@ -180,6 +187,7 @@ public static function manyToMantTableProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function columnsPropertyProvider(): array
     {
         return [
@@ -191,6 +199,7 @@ public static function columnsPropertyProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function keyProvider(): array
     {
         return [
@@ -202,14 +211,14 @@ public static function keyProvider(): array
     }
 
     #[DataProvider('tableEntityProvider')]
-    public function test_table_and_entities_methods($table, $entity): void
+    public function testTableAndEntitiesMethods(string $table, string $entity): void
     {
         $this->assertEquals($entity, $this->style->styledName($table));
         $this->assertEquals($table, $this->style->realName($entity));
     }
 
     #[DataProvider('columnsPropertyProvider')]
-    public function test_columns_and_properties_methods($column): void
+    public function testColumnsAndPropertiesMethods(string $column): void
     {
         $this->assertEquals($column, $this->style->styledProperty($column));
         $this->assertEquals($column, $this->style->realProperty($column));
@@ -218,13 +227,13 @@ public function test_columns_and_properties_methods($column): void
     }
 
     #[DataProvider('manyToMantTableProvider')]
-    public function test_table_from_left_right_table($left, $right, $table): void
+    public function testTableFromLeftRightTable(string $left, string $right, string $table): void
     {
         $this->assertEquals($table, $this->style->composed($left, $right));
     }
 
     #[DataProvider('keyProvider')]
-    public function test_keys($table, $foreign): void
+    public function testKeys(string $table, string $foreign): void
     {
         $this->assertTrue($this->style->isRemoteIdentifier($foreign));
         $this->assertEquals($table, $this->style->remoteFromIdentifier($foreign));
@@ -232,14 +241,14 @@ public function test_keys($table, $foreign): void
         $this->assertEquals($foreign, $this->style->remoteIdentifier($table));
     }
 
-    public function test_fetching_entity_typed(): void
+    public function testFetchingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->Comments[8]->fetch();
         $this->assertInstanceOf(__NAMESPACE__ . '\Comments', $comment);
     }
 
-    public function test_fetching_all_entity_typed(): void
+    public function testFetchingAllEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->Comments->fetchAll();
@@ -247,19 +256,25 @@ public function test_fetching_all_entity_typed(): void
 
         $categories = $mapper->PostCategories->Categories->fetch();
         $this->assertInstanceOf(__NAMESPACE__ . '\PostCategories', $categories);
-        $this->assertInstanceOf(__NAMESPACE__ . '\Categories', $categories->CategoryID);
+        $this->assertInstanceOf(
+            __NAMESPACE__ . '\Categories',
+            $categories->CategoryID,
+        );
     }
 
-    public function test_fetching_all_entity_typed_nested(): void
+    public function testFetchingAllEntityTypedNested(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->Comments->Posts->Authors->fetchAll();
         $this->assertInstanceOf(__NAMESPACE__ . '\Comments', $comment[0]);
         $this->assertInstanceOf(__NAMESPACE__ . '\Posts', $comment[0]->PostID);
-        $this->assertInstanceOf(__NAMESPACE__ . '\Authors', $comment[0]->PostID->AuthorID);
+        $this->assertInstanceOf(
+            __NAMESPACE__ . '\Authors',
+            $comment[0]->PostID->AuthorID,
+        );
     }
 
-    public function test_persisting_entity_typed(): void
+    public function testPersistingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->Comments[8]->fetch();
@@ -267,45 +282,67 @@ public function test_persisting_entity_typed(): void
         $comment->Text = 'HeyHey';
         $mapper->Comments->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select Text from Comments where CommentID=8')->fetchColumn(0);
+        $result = $this->conn->query(
+            'select Text from Comments where CommentID=8',
+        )->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
-    public function test_persisting_new_entity_typed(): void
+    public function testPersistingNewEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = new Comments();
         $comment->Text = 'HeyHey';
         $mapper->Comments->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select Text from Comments where CommentID=9')->fetchColumn(0);
+        $result = $this->conn->query(
+            'select Text from Comments where CommentID=9',
+        )->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 }
 
-
-
 class Posts
 {
-    public $PostID, $Title, $Text, $AuthorID;
+    public mixed $PostID = null;
+
+    public string|null $Title = null;
+
+    public string|null $Text = null;
+
+    public mixed $AuthorID = null;
 }
 
 class Authors
 {
-    public $AuthorID, $Name;
+    public mixed $AuthorID = null;
+
+    public string|null $Name = null;
 }
 
 class Comments
 {
-    public $CommentID, $PostID, $Text;
+    public mixed $CommentID = null;
+
+    public mixed $PostID = null;
+
+    public string|null $Text = null;
 }
 
 class Categories
 {
-    public $CategoryID, $Name, $Description;
+    public mixed $CategoryID = null;
+
+    public string|null $Name = null;
+
+    public string|null $Description = null;
 }
 
 class PostCategories
 {
-    public $PostCategoryID, $PostID, $CategoryID;
+    public mixed $PostCategoryID = null;
+
+    public mixed $PostID = null;
+
+    public mixed $CategoryID = null;
 }
diff --git a/tests/Styles/PluralTest.php b/tests/Styles/PluralTest.php
index b484cb7..3787fcd 100644
--- a/tests/Styles/PluralTest.php
+++ b/tests/Styles/PluralTest.php
@@ -22,15 +22,20 @@ class PluralTest extends TestCase
 
     private PDO $conn;
 
-    private $posts;
+    /** @var list<object> */
+    private array $posts;
 
-    private $authors;
+    /** @var list<object> */
+    private array $authors;
 
-    private $comments;
+    /** @var list<object> */
+    private array $comments;
 
-    private $categories;
+    /** @var list<object> */
+    private array $categories;
 
-    private $postsCategories;
+    /** @var list<object> */
+    private array $postsCategories;
 
     protected function setUp(): void
     {
@@ -157,7 +162,7 @@ protected function setUp(): void
     }
 
     #[DataProvider('tableEntityProvider')]
-    public function test_table_and_entities_methods($table, $entity): void
+    public function testTableAndEntitiesMethods(string $table, string $entity): void
     {
         $this->assertEquals($entity, $this->style->styledName($table));
         $this->assertEquals($table, $this->style->realName($entity));
@@ -165,7 +170,7 @@ public function test_table_and_entities_methods($table, $entity): void
     }
 
     #[DataProvider('columnsPropertyProvider')]
-    public function test_columns_and_properties_methods($column): void
+    public function testColumnsAndPropertiesMethods(string $column): void
     {
         $this->assertEquals($column, $this->style->styledProperty($column));
         $this->assertEquals($column, $this->style->realProperty($column));
@@ -174,27 +179,27 @@ public function test_columns_and_properties_methods($column): void
     }
 
     #[DataProvider('manyToMantTableProvider')]
-    public function test_table_from_left_right_table($left, $right, $table): void
+    public function testTableFromLeftRightTable(string $left, string $right, string $table): void
     {
         $this->assertEquals($table, $this->style->composed($left, $right));
     }
 
     #[DataProvider('foreignProvider')]
-    public function test_foreign($table, $foreign): void
+    public function testForeign(string $table, string $foreign): void
     {
         $this->assertTrue($this->style->isRemoteIdentifier($foreign));
         $this->assertEquals($table, $this->style->remoteFromIdentifier($foreign));
         $this->assertEquals($foreign, $this->style->remoteIdentifier($table));
     }
 
-    public function test_fetching_entity_typed(): void
+    public function testFetchingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comments[8]->fetch();
         $this->assertInstanceOf(__NAMESPACE__ . '\Comment', $comment);
     }
 
-    public function test_fetching_all_entity_typed(): void
+    public function testFetchingAllEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comments->fetchAll();
@@ -202,19 +207,25 @@ public function test_fetching_all_entity_typed(): void
 
         $categories = $mapper->posts_categories->categories->fetch();
         $this->assertInstanceOf(__NAMESPACE__ . '\PostCategory', $categories);
-        $this->assertInstanceOf(__NAMESPACE__ . '\Category', $categories->category_id);
+        $this->assertInstanceOf(
+            __NAMESPACE__ . '\Category',
+            $categories->category_id,
+        );
     }
 
-    public function test_fetching_all_entity_typed_nested(): void
+    public function testFetchingAllEntityTypedNested(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comments->posts->authors->fetchAll();
         $this->assertInstanceOf(__NAMESPACE__ . '\Comment', $comment[0]);
         $this->assertInstanceOf(__NAMESPACE__ . '\Post', $comment[0]->post_id);
-        $this->assertInstanceOf(__NAMESPACE__ . '\Author', $comment[0]->post_id->author_id);
+        $this->assertInstanceOf(
+            __NAMESPACE__ . '\Author',
+            $comment[0]->post_id->author_id,
+        );
     }
 
-    public function test_persisting_entity_typed(): void
+    public function testPersistingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comments[8]->fetch();
@@ -222,21 +233,26 @@ public function test_persisting_entity_typed(): void
         $comment->text = 'HeyHey';
         $mapper->comments->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select text from comments where id=8')->fetchColumn(0);
+        $result = $this->conn->query(
+            'select text from comments where id=8',
+        )->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
-    public function test_persisting_new_entity_typed(): void
+    public function testPersistingNewEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = new Comment();
         $comment->text = 'HeyHey';
         $mapper->comments->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select text from comments where id=9')->fetchColumn(0);
+        $result = $this->conn->query(
+            'select text from comments where id=9',
+        )->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
+    /** @return array<int, array<int, string>> */
     public static function tableEntityProvider(): array
     {
         return [
@@ -248,6 +264,7 @@ public static function tableEntityProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function manyToMantTableProvider(): array
     {
         return [
@@ -257,6 +274,7 @@ public static function manyToMantTableProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function columnsPropertyProvider(): array
     {
         return [
@@ -268,6 +286,7 @@ public static function columnsPropertyProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function foreignProvider(): array
     {
         return [
@@ -281,21 +300,43 @@ public static function foreignProvider(): array
 
 class Post
 {
-    public $id, $title, $text, $author_id;
+    public mixed $id = null;
+
+    public string|null $title = null;
+
+    public string|null $text = null;
+
+    public mixed $author_id = null;
 }
+
 class Author
 {
-    public $id, $name;
+    public mixed $id = null;
+
+    public string|null $name = null;
 }
+
 class Comment
 {
-    public $id, $post_id, $text;
+    public mixed $id = null;
+
+    public mixed $post_id = null;
+
+    public string|null $text = null;
 }
+
 class Category
 {
-    public $id, $name;
+    public mixed $id = null;
+
+    public string|null $name = null;
 }
+
 class PostCategory
 {
-    public $id, $post_id, $category_id;
+    public mixed $id = null;
+
+    public mixed $post_id = null;
+
+    public mixed $category_id = null;
 }
diff --git a/tests/Styles/SakilaTest.php b/tests/Styles/SakilaTest.php
index c1a40bf..8297805 100644
--- a/tests/Styles/SakilaTest.php
+++ b/tests/Styles/SakilaTest.php
@@ -22,15 +22,20 @@ class SakilaTest extends TestCase
 
     private PDO $conn;
 
-    private $posts;
+    /** @var list<object> */
+    private array $posts;
 
-    private $authors;
+    /** @var list<object> */
+    private array $authors;
 
-    private $comments;
+    /** @var list<object> */
+    private array $comments;
 
-    private $categories;
+    /** @var list<object> */
+    private array $categories;
 
-    private $postsCategories;
+    /** @var list<object> */
+    private array $postsCategories;
 
     protected function setUp(): void
     {
@@ -161,6 +166,7 @@ protected function setUp(): void
         $this->mapper->entityNamespace = __NAMESPACE__ . '\\';
     }
 
+    /** @return array<int, array<int, string>> */
     public static function tableEntityProvider(): array
     {
         return [
@@ -172,6 +178,7 @@ public static function tableEntityProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function manyToMantTableProvider(): array
     {
         return [
@@ -181,6 +188,7 @@ public static function manyToMantTableProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function columnsPropertyProvider(): array
     {
         return [
@@ -192,6 +200,7 @@ public static function columnsPropertyProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function keyProvider(): array
     {
         return [
@@ -203,14 +212,14 @@ public static function keyProvider(): array
     }
 
     #[DataProvider('tableEntityProvider')]
-    public function test_table_and_entities_methods($table, $entity): void
+    public function testTableAndEntitiesMethods(string $table, string $entity): void
     {
         $this->assertEquals($entity, $this->style->styledName($table));
         $this->assertEquals($table, $this->style->realName($entity));
     }
 
     #[DataProvider('columnsPropertyProvider')]
-    public function test_columns_and_properties_methods($column): void
+    public function testColumnsAndPropertiesMethods(string $column): void
     {
         $this->assertEquals($column, $this->style->styledProperty($column));
         $this->assertEquals($column, $this->style->realProperty($column));
@@ -219,13 +228,13 @@ public function test_columns_and_properties_methods($column): void
     }
 
     #[DataProvider('manyToMantTableProvider')]
-    public function test_table_from_left_right_table($left, $right, $table): void
+    public function testTableFromLeftRightTable(string $left, string $right, string $table): void
     {
         $this->assertEquals($table, $this->style->composed($left, $right));
     }
 
     #[DataProvider('keyProvider')]
-    public function test_foreign($table, $key): void
+    public function testForeign(string $table, string $key): void
     {
         $this->assertTrue($this->style->isRemoteIdentifier($key));
         $this->assertEquals($table, $this->style->remoteFromIdentifier($key));
@@ -233,14 +242,14 @@ public function test_foreign($table, $key): void
         $this->assertEquals($key, $this->style->remoteIdentifier($table));
     }
 
-    public function test_fetching_entity_typed(): void
+    public function testFetchingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comment[8]->fetch();
         $this->assertInstanceOf(__NAMESPACE__ . '\Comment', $comment);
     }
 
-    public function test_fetching_all_entity_typed(): void
+    public function testFetchingAllEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comment->fetchAll();
@@ -248,19 +257,25 @@ public function test_fetching_all_entity_typed(): void
 
         $categories = $mapper->post_category->category->fetch();
         $this->assertInstanceOf(__NAMESPACE__ . '\PostCategory', $categories);
-        $this->assertInstanceOf(__NAMESPACE__ . '\Category', $categories->category_id);
+        $this->assertInstanceOf(
+            __NAMESPACE__ . '\Category',
+            $categories->category_id,
+        );
     }
 
-    public function test_fetching_all_entity_typed_nested(): void
+    public function testFetchingAllEntityTypedNested(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comment->post->author->fetchAll();
         $this->assertInstanceOf(__NAMESPACE__ . '\Comment', $comment[0]);
         $this->assertInstanceOf(__NAMESPACE__ . '\Post', $comment[0]->post_id);
-        $this->assertInstanceOf(__NAMESPACE__ . '\Author', $comment[0]->post_id->author_id);
+        $this->assertInstanceOf(
+            __NAMESPACE__ . '\Author',
+            $comment[0]->post_id->author_id,
+        );
     }
 
-    public function test_persisting_entity_typed(): void
+    public function testPersistingEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = $mapper->comment[8]->fetch();
@@ -268,39 +283,69 @@ public function test_persisting_entity_typed(): void
         $comment->text = 'HeyHey';
         $mapper->comment->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select text from comment where comment_id=8')->fetchColumn(0);
+        $result = $this->conn->query(
+            'select text from comment where comment_id=8',
+        )->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 
-    public function test_persisting_new_entity_typed(): void
+    public function testPersistingNewEntityTyped(): void
     {
         $mapper = $this->mapper;
         $comment = new Comment();
         $comment->text = 'HeyHey';
         $mapper->comment->persist($comment);
         $mapper->flush();
-        $result = $this->conn->query('select text from comment where comment_id=9')->fetchColumn(0);
+        $result = $this->conn->query(
+            'select text from comment where comment_id=9',
+        )->fetchColumn(0);
         $this->assertEquals('HeyHey', $result);
     }
 }
 
 class Post
 {
-    public $post_id, $title, $text, $author_id;
+    public mixed $post_id = null;
+
+    public string|null $title = null;
+
+    public string|null $text = null;
+
+    public mixed $author_id = null;
 }
+
 class Author
 {
-    public $author_id, $name;
+    public mixed $author_id = null;
+
+    public string|null $name = null;
 }
+
 class Comment
 {
-    public $comment_id, $post_id, $text;
+    public mixed $comment_id = null;
+
+    public mixed $post_id = null;
+
+    public string|null $text = null;
 }
+
 class Category
 {
-    public $category_id, $name, $content, $description;
+    public mixed $category_id = null;
+
+    public string|null $name = null;
+
+    public string|null $content = null;
+
+    public string|null $description = null;
 }
+
 class PostCategory
 {
-    public $post_category_id, $post_id, $category_id;
+    public mixed $post_category_id = null;
+
+    public mixed $post_id = null;
+
+    public mixed $category_id = null;
 }
diff --git a/tests/Styles/StandardTest.php b/tests/Styles/StandardTest.php
index 80e992e..68c6b56 100644
--- a/tests/Styles/StandardTest.php
+++ b/tests/Styles/StandardTest.php
@@ -18,6 +18,7 @@ protected function setUp(): void
         $this->style = new Standard();
     }
 
+    /** @return array<int, array<int, string>> */
     public static function tableEntityProvider(): array
     {
         return [
@@ -29,6 +30,7 @@ public static function tableEntityProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function manyToMantTableProvider(): array
     {
         return [
@@ -38,6 +40,7 @@ public static function manyToMantTableProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function columnsPropertyProvider(): array
     {
         return [
@@ -49,6 +52,7 @@ public static function columnsPropertyProvider(): array
         ];
     }
 
+    /** @return array<int, array<int, string>> */
     public static function foreignProvider(): array
     {
         return [
@@ -60,7 +64,7 @@ public static function foreignProvider(): array
     }
 
     #[DataProvider('tableEntityProvider')]
-    public function test_table_and_entities_methods($table, $entity): void
+    public function testTableAndEntitiesMethods(string $table, string $entity): void
     {
         $this->assertEquals($entity, $this->style->styledName($table));
         $this->assertEquals($table, $this->style->realName($entity));
@@ -68,7 +72,7 @@ public function test_table_and_entities_methods($table, $entity): void
     }
 
     #[DataProvider('columnsPropertyProvider')]
-    public function test_columns_and_properties_methods($name): void
+    public function testColumnsAndPropertiesMethods(string $name): void
     {
         $this->assertEquals($name, $this->style->styledProperty($name));
         $this->assertEquals($name, $this->style->realProperty($name));
@@ -77,13 +81,13 @@ public function test_columns_and_properties_methods($name): void
     }
 
     #[DataProvider('manyToMantTableProvider')]
-    public function test_table_from_left_right_table($left, $right, $table): void
+    public function testTableFromLeftRightTable(string $left, string $right, string $table): void
     {
         $this->assertEquals($table, $this->style->composed($left, $right));
     }
 
     #[DataProvider('foreignProvider')]
-    public function test_foreign($table, $foreign): void
+    public function testForeign(string $table, string $foreign): void
     {
         $this->assertTrue($this->style->isRemoteIdentifier($foreign));
         $this->assertEquals($table, $this->style->remoteFromIdentifier($foreign));