1 files changed, 55 insertions, 0 deletions
diff --git a/testing/web-platform/tests/scroll-animations/css/pseudo-on-scroller.html b/testing/web-platform/tests/scroll-animations/css/pseudo-on-scroller.html
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index 0000000000..8dd49ce4d8
--- /dev/null
+++ b/testing/web-platform/tests/scroll-animations/css/pseudo-on-scroller.html
@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>Animating pseduo-element on scroller</title>
+</head>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/web-animations/testcommon.js"></script>
+<script src="testcommon.js"></script>
+<style type="text/css">
+.scroller {
+  overflow: auto;
+  width: 100px;
+  height: 100px;
+  margin: 1em;
+  outline: 1px solid;
+  animation: bg linear;
+  animation-timeline: scroll(self inline);
+}
+.pseudo::before {
+  content: "";
+  display: block;
+  width: 200px;
+  height: 50px;
+  background: red;
+  animation: bg linear reverse;
+  animation-timeline: scroll(inline);
+}
+@keyframes bg {
+  from {
+    background: rgb(0, 255, 0);
+  }
+  to {
+    background: rgb(0, 0, 255);
+  }
+}
+</style>
+<body>
+  <div class="scroller pseudo"></div>
+  <div id="log"></div>
+</body>
+<script type="text/javascript">
+  'use strict';
+
+  promise_test(async t => {
+    const scroller = document.querySelector('.scroller');
+    await waitForNextFrame();
+    assert_equals(getComputedStyle(scroller).backgroundColor, 'rgb(0, 255, 0)');
+    assert_equals(getComputedStyle(scroller, ':before').backgroundColor,
+                  'rgb(0, 0, 255)');
+  }, `scroll nearest on pseudo-element attaches to parent scroll container`);
+</script>
+</html>