diff --git a/lam/tests/lib/LAMConfigTest.php b/lam/tests/lib/LAMConfigTest.php
index f41da59f..2d887992 100644
--- a/lam/tests/lib/LAMConfigTest.php
+++ b/lam/tests/lib/LAMConfigTest.php
@@ -41,7 +41,7 @@ class LAMConfigTest extends TestCase {
 	/**
 	 * Prepares the environment before running a test.
 	 */
-	protected function setUp() {
+	protected function setUp(): void {
 		parent::setUp();
 		testCreateDefaultConfig();
 		$profiles = getConfigProfiles();