diff --git a/.gitignore b/.gitignore
index d8a7996..47342dc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 composer.lock
 vendor/
+.phpunit.result.cache
diff --git a/test/CommonMarkTestStrict.php b/test/CommonMarkTestStrict.php
index 9a007e2..4aa26dc 100644
--- a/test/CommonMarkTestStrict.php
+++ b/test/CommonMarkTestStrict.php
@@ -13,7 +13,7 @@ class CommonMarkTestStrict extends TestCase
 
     protected $parsedown;
 
-    protected function setUp()
+    protected function setUp() : void
     {
         $this->parsedown = new TestParsedown();
         $this->parsedown->setUrlsLinked(false);
diff --git a/test/CommonMarkTestWeak.php b/test/CommonMarkTestWeak.php
index ef4081a..8d0bb4a 100644
--- a/test/CommonMarkTestWeak.php
+++ b/test/CommonMarkTestWeak.php
@@ -17,7 +17,7 @@ class CommonMarkTestWeak extends CommonMarkTestStrict
 {
     protected $textLevelElementRegex;
 
-    protected function setUp()
+    protected function setUp() : void
     {
         parent::setUp();