Enable phpstan-phpunit

Author: ruudk

composer.json

@@ -22,6 +22,7 @@
         "friendsofphp/php-cs-fixer": "^3.85",
         "phpstan/extension-installer": "^1.4",
         "phpstan/phpstan": "^2.1",
+        "phpstan/phpstan-phpunit": "^2.0",
         "phpunit/phpunit": "^12.3",
         "ruudk/readme-examples-sync-hook": "^1.0",
         "shipmonk/composer-dependency-analyser": "^1.8",

composer.lock

@@ -47,7 +47,6 @@ public function testConstructorWithNestedGroups() : void
         $group = new Group($lines);
 
         self::assertSame($lines, $group->lines);
-        self::assertInstanceOf(Group::class, $group->lines[1]);
     }
 
     public function testConstructorWithGenerator() : void
@@ -160,7 +159,6 @@ public function testComplexNestedStructure() : void
         self::assertFalse($outerGroup->isEmpty());
 
         $middleGroupFromOuter = $outerGroup->lines[1];
-        self::assertInstanceOf(Group::class, $middleGroupFromOuter);
         self::assertSame(0, $middleGroupFromOuter->indention);
         self::assertCount(2, $middleGroupFromOuter->lines);