diff --git a/tests/App/DummyEnvelope.php b/stubs/DummyEnvelope.php
similarity index 75%
rename from tests/App/DummyEnvelope.php
rename to stubs/DummyEnvelope.php
index e92fbeec..b609efe3 100644
--- a/tests/App/DummyEnvelope.php
+++ b/stubs/DummyEnvelope.php
@@ -2,11 +2,16 @@
 
 declare(strict_types=1);
 
-namespace Yiisoft\Queue\Tests\App;
+namespace Yiisoft\Queue\Stubs;
 
 use Yiisoft\Queue\Message\Envelope;
 use Yiisoft\Queue\Message\MessageInterface;
 
+/**
+ * Dummy envelope stub for testing purposes.
+ *
+ * @extends Envelope<array<string, mixed>>
+ */
 final class DummyEnvelope extends Envelope
 {
     public function __construct(MessageInterface $message)
diff --git a/tests/Unit/Message/EnvelopeTest.php b/tests/Unit/Message/EnvelopeTest.php
index a27b8bf8..2ba98f84 100644
--- a/tests/Unit/Message/EnvelopeTest.php
+++ b/tests/Unit/Message/EnvelopeTest.php
@@ -6,7 +6,7 @@
 
 use LogicException;
 use PHPUnit\Framework\TestCase;
-use Yiisoft\Queue\Tests\App\DummyEnvelope;
+use Yiisoft\Queue\Stubs\DummyEnvelope;
 
 final class EnvelopeTest extends TestCase
 {