diff --git a/tests/BrowserFactoryTest.php b/tests/BrowserFactoryTest.php
index b1e2d82..2f38721 100644
--- a/tests/BrowserFactoryTest.php
+++ b/tests/BrowserFactoryTest.php
@@ -124,7 +124,7 @@ public function testConnectToBrowser(): void
 
         // create a page on the first browser after 2nd connection
         $page2 = $browser->createPage();
-        sleep(1);
+        \sleep(1);
         $page2TargetId = $page2->getSession()->getTargetId();
 
         // update 2nd browser
diff --git a/tests/BrowsingTest.php b/tests/BrowsingTest.php
index 206e1ad..ff7e2ce 100644
--- a/tests/BrowsingTest.php
+++ b/tests/BrowsingTest.php
@@ -145,7 +145,7 @@ public function testGetPagesClose(): void
 
         $page->close();
 
-        sleep(1);
+        \sleep(1);
 
         $finalCount = \count(self::$browser->getPages());