diff --git a/src/Testing/TestCase.neon b/src/Testing/TestCase.neon
index 4040078660..627dd41a5e 100644
--- a/src/Testing/TestCase.neon
+++ b/src/Testing/TestCase.neon
@@ -11,11 +11,6 @@ services:
 			fileExtensions: %fileExtensions%
 			excludePaths: %excludePaths%
 
-	# overrides service from services.neon
-	cacheStorage:
-		class: PHPStan\Cache\MemoryCacheStorage
-		arguments!: []
-
 	# overrides service from parsers.neon
 	currentPhpVersionSimpleParser!:
 		factory: @currentPhpVersionRichParser
diff --git a/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.neon b/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.neon
new file mode 100644
index 0000000000..17c72730f7
--- /dev/null
+++ b/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.neon
@@ -0,0 +1,5 @@
+services:
+	# overrides service from services.neon
+	cacheStorage:
+		class: PHPStan\Cache\MemoryCacheStorage
+		arguments!: []
diff --git a/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.php b/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.php
index 30b555e7b3..751520456b 100644
--- a/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.php
+++ b/tests/PHPStan/Reflection/BetterReflection/SourceLocator/OptimizedDirectorySourceLocatorTest.php
@@ -12,6 +12,7 @@
 use TestDirectorySourceLocator\AFoo;
 use TestDirectorySourceLocator\EmptyClass;
 use function array_map;
+use function array_merge;
 use function basename;
 use const PHP_VERSION_ID;
 
@@ -317,4 +318,14 @@ public function testBug5525(): void
 		$this->assertSame('Faker\\Provider\\nl_BE\\Text', $className);
 	}
 
+	public static function getAdditionalConfigFiles(): array
+	{
+		return array_merge(
+			parent::getAdditionalConfigFiles(),
+			[
+				__DIR__ . '/OptimizedDirectorySourceLocatorTest.neon',
+			],
+		);
+	}
+
 }