1 files changed, 2 insertions, 1 deletions
diff --git a/testing/web-platform/tests/css/css-scoping/font-face-004.html b/testing/web-platform/tests/css/css-scoping/font-face-004.html
index 6ac50bd432..f68e70994f 100644
--- a/testing/web-platform/tests/css/css-scoping/font-face-004.html
+++ b/testing/web-platform/tests/css/css-scoping/font-face-004.html
@@ -14,7 +14,7 @@
 </style>
 <div id="host"><span id="in-document">1234567890</span></div>
 <script>
-test(function() {
+promise_test(async function() {
   host.attachShadow({ mode: "open" }).innerHTML = `
     <style>
       ::slotted(#in-document) {
@@ -25,6 +25,7 @@ test(function() {
     <span id="in-shadow">0123456789</span>
   `;
 
+  await document.fonts.ready;
   assert_equals(document.getElementById('in-document').offsetWidth, 160);
   assert_not_equals(host.shadowRoot.getElementById('in-shadow').offsetWidth, 160);
 }, "@font-face from document applies to a slotted element");