1 files changed, 47 insertions, 0 deletions
diff --git a/testing/web-platform/tests/css/cssom-view/add-background-attachment-fixed-during-smooth-scroll.html b/testing/web-platform/tests/css/cssom-view/add-background-attachment-fixed-during-smooth-scroll.html
new file mode 100644
index 0000000000..6600c0e055
--- /dev/null
+++ b/testing/web-platform/tests/css/cssom-view/add-background-attachment-fixed-during-smooth-scroll.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+<title>Add background-attachment:fixed during smooth scroll</title>
+<link rel="help" href="https://drafts.csswg.org/cssom-view/#dictdef-scrolltooptions">
+<link rel="match" href="add-background-attachment-fixed-during-smooth-scroll-ref.html">
+<meta name="fuzzy" content="maxDifference=0-2; totalPixels=0-27000">
+<script src="/common/reftest-wait.js"></script>
+<style>
+#container {
+  width: 200px;
+  height: 200px;
+  overflow: scroll;
+  background: linear-gradient(green, blue);
+  will-change: scroll-position;
+}
+#content {
+  width: 7500px;
+  height: 7500px;
+}
+</style>
+<script>
+function startSmoothScroll() {
+  var scrollToOptions = {behavior: "smooth", top: 6000};
+  container.scrollTo(scrollToOptions);
+  requestAnimationFrame(preventCompositedScrolling);
+}
+
+function preventCompositedScrolling() {
+  container.style.backgroundAttachment = "fixed";
+  requestAnimationFrame(waitForSmoothScrollEnd);
+}
+
+function waitForSmoothScrollEnd() {
+  if (container.scrollTop == 6000) {
+    takeScreenshot();
+  } else {
+    window.requestAnimationFrame(waitForSmoothScrollEnd);
+  }
+}
+
+onload = () => {
+  requestAnimationFrame(startSmoothScroll);
+}
+</script>
+<div id="container">
+  <div id="content">Content</div>
+</div>