1 files changed, 52 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/semantics/embedded-content/the-iframe-element/iframe-loading-lazy-in-scroller-horizontal.html b/testing/web-platform/tests/html/semantics/embedded-content/the-iframe-element/iframe-loading-lazy-in-scroller-horizontal.html
new file mode 100644
index 0000000000..80ba0829a9
--- /dev/null
+++ b/testing/web-platform/tests/html/semantics/embedded-content/the-iframe-element/iframe-loading-lazy-in-scroller-horizontal.html
@@ -0,0 +1,52 @@
+<!DOCTYPE html>
+<link rel="help" href="https://html.spec.whatwg.org/#lazy-load-root-margin">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<style>
+  #scroller {
+    width: 100px;
+    height: 100px;
+    overflow: scroll;
+    background-color: gray;
+    display: flex;
+  }
+
+  #spacer {
+    width: 130px;
+    height: 130px;
+    flex-shrink: 0;
+  }
+
+  #target {
+    width: 100px;
+    height: 100px;
+    flex-shrink: 0;
+  }
+</style>
+
+<div id="scroller">
+  <div id="spacer"></div>
+  <iframe
+    id="target"
+    src="resources/green.png"
+    loading="lazy"
+    onload="iframe_onload();"
+  ></iframe>
+</div>
+
+<script>
+  const t = async_test(
+    "Test that lazy-loaded iframes load when near viewport."
+  );
+
+  function iframe_onload() {
+    t.done();
+  }
+
+  t.step_timeout(() => {
+    t.unreached_func(
+      "Timed out while waiting for iframe to load."
+    )();
+  }, 2000);
+</script>