1 files changed, 36 insertions, 0 deletions
diff --git a/testing/web-platform/tests/scroll-animations/scroll-timelines/source-quirks-mode.html b/testing/web-platform/tests/scroll-animations/scroll-timelines/source-quirks-mode.html
new file mode 100644
index 0000000000..17e95a0519
--- /dev/null
+++ b/testing/web-platform/tests/scroll-animations/scroll-timelines/source-quirks-mode.html
@@ -0,0 +1,36 @@
+<!-- Quirks mode -->
+<html>
+<head>
+  <title>ScrollTimeline default source in quirks mode</title>
+  <link rel="help" href="https://drafts.csswg.org/scroll-animations-1/#dom-scrolltimeline-scrolltimeline">
+  <script src="/resources/testharness.js"></script>
+  <script src="/resources/testharnessreport.js"></script>
+  <style>
+    /* This is just to make it possible for #body1 to be
+       "potentially scrollable".
+
+       https://drafts.csswg.org/cssom-view/#potentially-scrollable */
+    html {
+      overflow: hidden;
+    }
+  </style>
+</head>
+<body id=body1></body>
+<script>
+test(() => {
+  try {
+    assert_equals(document.scrollingElement.id, 'body1');
+    assert_equals(new ScrollTimeline({}).source, body1);
+
+    // Make #body1 "potentially scrollable". This causes the scrollingElement
+    // of the document to become null.
+    //
+    // https://drafts.csswg.org/cssom-view/#dom-document-scrollingelement
+    body1.style = 'overflow:scroll';
+    assert_equals(new ScrollTimeline({}).source, null);
+  } finally {
+    body1.style = '';
+  }
+}, 'Style of <body> is reflected in source attribute in quirks mode');
+</script>
+</html>