1 files changed, 46 insertions, 0 deletions
diff --git a/testing/web-platform/tests/intersection-observer/scroll-margin-iframe.html b/testing/web-platform/tests/intersection-observer/scroll-margin-iframe.html
new file mode 100644
index 0000000000..1d63c65169
--- /dev/null
+++ b/testing/web-platform/tests/intersection-observer/scroll-margin-iframe.html
@@ -0,0 +1,46 @@
+<!DOCTYPE html>
+<meta name="viewport" content="width=device-width,initial-scale=1">
+<link rel="help" href="https://www.w3.org/TR/intersection-observer/#dom-intersectionobserver-scrollmargin">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="./resources/intersection-observer-test-utils.js"></script>
+
+<iframe
+  id="target-iframe"
+  src="resources/iframe-no-root-subframe.html"
+  width="300"
+  height="200"
+></iframe>
+
+<script>
+var iframe = document.getElementById("target-iframe");
+var target;
+var entries = [];
+
+iframe.onload = function() {
+  runTestCycle(function() {
+    assert_true(!!iframe, "iframe exists");
+
+    target = iframe.contentDocument.getElementById("target");
+    assert_true(!!target, "Target element exists.");
+
+    var observer = new IntersectionObserver(function(changes) {
+      entries = entries.concat(changes)
+    }, {
+      scrollMargin: "18px"
+    });
+    observer.observe(target);
+
+    entries = entries.concat(observer.takeRecords());
+    assert_equals(entries.length, 0, "No initial notifications.");
+
+    runTestCycle(testIntersection, "Test scroll margin intersection");
+  }, "Observer with the implicit root; target in a same-origin iframe.");
+};
+
+function testIntersection() {
+  assert_equals(entries.length, 1, "IntersectionObserverEntryCount");
+  assert_true(entries[0].isIntersecting, "isIntersecting");
+  assert_approx_equals(entries[0].intersectionRatio, 0.1, 0.001, "intersectionRatio");
+}
+</script>