diff --git a/tests/classes/models/coursework_test.php b/tests/classes/models/coursework_test.php
index c2e901b0..434b3e33 100644
--- a/tests/classes/models/coursework_test.php
+++ b/tests/classes/models/coursework_test.php
@@ -60,7 +60,7 @@ public function setUp(): void {
     /**
      * Clean up the test fixture by removing the objects.
      */
-    public function tearDown() {
+    public function tearDown(): void {
         global $DB;
 
         $DB->delete_records('coursework', array('id' => $this->coursework->id));
diff --git a/tests/classes/models/submission_test.php b/tests/classes/models/submission_test.php
index 15db4d4d..22fdd492 100644
--- a/tests/classes/models/submission_test.php
+++ b/tests/classes/models/submission_test.php
@@ -56,7 +56,7 @@ public function setUp(): void {
     /**
      * Clean up the test fixture by removing the objects.
      */
-    public function tearDown() {
+    public function tearDown(): void {
         global $DB;
 
         $DB->delete_records('coursework', array('id' => $this->coursework->id));
diff --git a/tests/generator_test.php b/tests/generator_test.php
index f4fac75f..49c24a31 100644
--- a/tests/generator_test.php
+++ b/tests/generator_test.php
@@ -44,7 +44,7 @@ class generator_test extends \advanced_testcase {
     /**
      * Sets things up for every test. We want all to clean up after themselves.
      */
-    public function setUp():void {
+    public function setUp(): void {
         $this->resetAfterTest(true);
     }