diff --git a/tests/src/Kernel/SqliteCachedKernelTestBase.php b/tests/src/Kernel/SqliteCachedKernelTestBase.php
index a9d6f19..e2a99e7 100755
--- a/tests/src/Kernel/SqliteCachedKernelTestBase.php
+++ b/tests/src/Kernel/SqliteCachedKernelTestBase.php
@@ -27,7 +27,7 @@ abstract class SqliteCachedKernelTestBase extends KernelTestBase {
   /**
    * {@inheritdoc}
    */
-  protected function setUp() {
+  protected function setUp(): void {
     parent::setUp();
 
     [$lastAvailableClassCache, $missingClassCaches] = $this->getCacheInfo();