diff --git a/tests/filter_test.php b/tests/filter_test.php
index 5b83ffa..63d8d7f 100644
--- a/tests/filter_test.php
+++ b/tests/filter_test.php
@@ -41,7 +41,7 @@ class filter_oembed_testcase extends advanced_testcase {
     /**
      * Sets up the test cases.
      */
-    protected function setUp() {
+    protected function setUp() :void {
         parent::setUp();
         $this->filter = new filter_oembed(context_system::instance(), array());
         // Ensure all tested providers are enabled.