diff --git a/tests/cases/Service/TestSerial.php b/tests/cases/Service/TestSerial.php
index 5a96078..7338137 100644
--- a/tests/cases/Service/TestSerial.php
+++ b/tests/cases/Service/TestSerial.php
@@ -13,7 +13,7 @@ use JKingWeb\Arsse\Service\Serial\Driver;
 
 /** @covers \JKingWeb\Arsse\Service\Serial\Driver */
 class TestSerial extends \JKingWeb\Arsse\Test\AbstractTest {
-    public function setUp() {
+    public function setUp(): void {
         self::clearData();
         self::setConf();
         Arsse::$db = \Phake::mock(Database::class);
diff --git a/tests/cases/Service/TestSubprocess.php b/tests/cases/Service/TestSubprocess.php
index c02c4b2..332b454 100644
--- a/tests/cases/Service/TestSubprocess.php
+++ b/tests/cases/Service/TestSubprocess.php
@@ -13,7 +13,7 @@ use JKingWeb\Arsse\Service\Subprocess\Driver;
 
 /** @covers \JKingWeb\Arsse\Service\Subprocess\Driver */
 class TestSubprocess extends \JKingWeb\Arsse\Test\AbstractTest {
-    public function setUp() {
+    public function setUp(): void {
         self::clearData();
         self::setConf();
     }
diff --git a/tests/cases/TestArsse.php b/tests/cases/TestArsse.php
index f28e7ee..9fbe082 100644
--- a/tests/cases/TestArsse.php
+++ b/tests/cases/TestArsse.php
@@ -15,10 +15,10 @@ use JKingWeb\Arsse\Service;
 
 /** @covers \JKingWeb\Arsse\Arsse */
 class TestArsse extends \JKingWeb\Arsse\Test\AbstractTest {
-    public function setUp() {
+    public function setUp(): void {
         self::clearData(false);
     }
-    public function tearDown() {
+    public function tearDown(): void {
         self::clearData();
     }