1 files changed, 34 insertions, 0 deletions
diff --git a/testing/web-platform/tests/dom/events/non-cancelable-when-passive/synthetic-events-cancelable.html b/testing/web-platform/tests/dom/events/non-cancelable-when-passive/synthetic-events-cancelable.html
new file mode 100644
index 0000000000..4287770b8d
--- /dev/null
+++ b/testing/web-platform/tests/dom/events/non-cancelable-when-passive/synthetic-events-cancelable.html
@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<title>Synthetic events are always cancelable by default</title>
+<link rel="help" href="https://dom.spec.whatwg.org/#dictdef-eventinit">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>
+const eventsMap = {
+  wheel: 'WheelEvent',
+  mousewheel: 'WheelEvent',
+  touchstart: 'TouchEvent',
+  touchmove: 'TouchEvent',
+  touchend: 'TouchEvent',
+  touchcancel: 'TouchEvent',
+}
+function isCancelable(eventName, interfaceName) {
+  test(() => {
+    assert_implements(interfaceName in self, `${interfaceName} should be supported`);
+    let defaultPrevented = null;
+    addEventListener(eventName, event => {
+      event.preventDefault();
+      defaultPrevented = event.defaultPrevented;
+    });
+    const event = new self[interfaceName](eventName);
+    assert_false(event.cancelable, 'cancelable');
+    const dispatchEventReturnValue = dispatchEvent(event);
+    assert_false(defaultPrevented, 'defaultPrevented');
+    assert_true(dispatchEventReturnValue, 'dispatchEvent() return value');
+  }, `Synthetic ${eventName} event with interface ${interfaceName} is not cancelable`);
+}
+for (const eventName in eventsMap) {
+  isCancelable(eventName, eventsMap[eventName]);
+  isCancelable(eventName, 'Event');
+}
+</script>