diff --git a/core/modules/serialization/tests/src/Unit/Normalizer/TimeStampItemNormalizerTraitDeprecatedTestClass.php b/core/modules/serialization/tests/serialization_test/src/TimeStampItemNormalizerTraitDeprecatedTestClass.php
similarity index 86%
rename from core/modules/serialization/tests/src/Unit/Normalizer/TimeStampItemNormalizerTraitDeprecatedTestClass.php
rename to core/modules/serialization/tests/serialization_test/src/TimeStampItemNormalizerTraitDeprecatedTestClass.php
index 500414a03d4..be63b1101c9 100644
--- a/core/modules/serialization/tests/src/Unit/Normalizer/TimeStampItemNormalizerTraitDeprecatedTestClass.php
+++ b/core/modules/serialization/tests/serialization_test/src/TimeStampItemNormalizerTraitDeprecatedTestClass.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\Tests\serialization\Unit\Normalizer;
+namespace Drupal\serialization_test;
 
 use Drupal\serialization\Normalizer\TimeStampItemNormalizerTrait;
 
diff --git a/core/modules/serialization/tests/src/Unit/Normalizer/TimeStampItemNormalizerTraitDeprecatedTest.php b/core/modules/serialization/tests/src/Unit/Normalizer/TimeStampItemNormalizerTraitDeprecatedTest.php
index 77623a190fc..d0a02e8aee8 100644
--- a/core/modules/serialization/tests/src/Unit/Normalizer/TimeStampItemNormalizerTraitDeprecatedTest.php
+++ b/core/modules/serialization/tests/src/Unit/Normalizer/TimeStampItemNormalizerTraitDeprecatedTest.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Tests\serialization\Unit\Normalizer;
 
+use Drupal\serialization_test\TimeStampItemNormalizerTraitDeprecatedTestClass;
 use Drupal\Tests\UnitTestCase;
 
 /**