1 files changed, 52 insertions, 0 deletions
diff --git a/testing/web-platform/tests/event-timing/first-input-interactionid-tap.html b/testing/web-platform/tests/event-timing/first-input-interactionid-tap.html
new file mode 100644
index 0000000000..f5e080eb16
--- /dev/null
+++ b/testing/web-platform/tests/event-timing/first-input-interactionid-tap.html
@@ -0,0 +1,52 @@
+<!DOCTYPE html>
+<html>
+<meta charset=utf-8 />
+<title>First Input: interactionId-tap.</title>
+<button id='testButtonId'>Tap me</button>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script src=/resources/testdriver.js></script>
+<script src=/resources/testdriver-vendor.js></script>
+<script src=/resources/testdriver-actions.js></script>
+<script src=resources/event-timing-test-utils.js></script>
+
+<script>
+  let firstInputInteractionId = 0;
+  let eventTimingPointerDownInteractionId = 0;
+  let hasFirstInputEntry = false;
+  let hasEventTimingPointerDownEntry = false;
+
+  promise_test(async t => {
+    assert_implements(window.PerformanceEventTiming, 'Event Timing is not supported.');
+
+    const callback = (entryList) => {
+      entryList.getEntries().forEach(entry => {
+        switch (entry.entryType) {
+          case 'first-input': {
+            firstInputInteractionId = entry.interactionId;
+            hasFirstInputEntry = true;
+            break;
+          }
+          case 'event': {
+            if ('pointerdown' == entry.name) {
+              eventTimingPointerDownInteractionId = entry.interactionId;
+              hasEventTimingPointerDownEntry = true;
+            }
+            break;
+          }
+        }
+      });
+    };
+    const readyToResolve = () => {
+      return hasFirstInputEntry && hasEventTimingPointerDownEntry;
+    }
+    const observerPromise = createPerformanceObserverPromise(['event', 'first-input'], callback, readyToResolve);
+    await interactAndObserve('tap', document.getElementById('testButtonId'), observerPromise);
+
+    assert_greater_than(firstInputInteractionId, 0, 'The first input entry should have a non-trivial interactionId');
+    assert_equals(firstInputInteractionId, eventTimingPointerDownInteractionId, 'The first input entry should have the same interactionId as the event timing pointerdown entry');
+
+  }, "The interactionId of the first input entry should match the same pointerdown entry of event timing when tap.");
+</script>
+
+</html>