1 files changed, 102 insertions, 0 deletions
diff --git a/testing/web-platform/tests/dom/events/EventListener-handleEvent.html b/testing/web-platform/tests/dom/events/EventListener-handleEvent.html
new file mode 100644
index 0000000000..06bc1f6e2a
--- /dev/null
+++ b/testing/web-platform/tests/dom/events/EventListener-handleEvent.html
@@ -0,0 +1,102 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title>EventListener::handleEvent()</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<link rel="help" href="https://dom.spec.whatwg.org/#callbackdef-eventlistener">
+<div id=log></div>
+<script>
+setup({ allow_uncaught_exception: true });
+
+test(function(t) {
+    var type = "foo";
+    var target = document.createElement("div");
+    var eventListener = {
+        handleEvent: function(evt) {
+            var that = this;
+            t.step(function() {
+                assert_equals(evt.type, type);
+                assert_equals(evt.target, target);
+                assert_equals(evt.srcElement, target);
+                assert_equals(that, eventListener);
+            });
+        },
+    };
+
+    target.addEventListener(type, eventListener);
+    target.dispatchEvent(new Event(type));
+}, "calls `handleEvent` method of `EventListener`");
+
+test(function(t) {
+    var type = "foo";
+    var target = document.createElement("div");
+    var calls = 0;
+
+    target.addEventListener(type, {
+        get handleEvent() {
+            calls++;
+            return function() {};
+        },
+    });
+
+    assert_equals(calls, 0);
+    target.dispatchEvent(new Event(type));
+    target.dispatchEvent(new Event(type));
+    assert_equals(calls, 2);
+}, "performs `Get` every time event is dispatched");
+
+test(function(t) {
+    var type = "foo";
+    var target = document.createElement("div");
+    var calls = 0;
+    var eventListener = function() { calls++; };
+    eventListener.handleEvent = t.unreached_func("`handleEvent` method should not be called on functions");
+
+    target.addEventListener(type, eventListener);
+    target.dispatchEvent(new Event(type));
+    assert_equals(calls, 1);
+}, "doesn't call `handleEvent` method on callable `EventListener`");
+
+const uncaught_error_test = async (t, getHandleEvent) => {
+    const type = "foo";
+    const target = document.createElement("div");
+
+    let calls = 0;
+    target.addEventListener(type, {
+        get handleEvent() {
+            calls++;
+            return getHandleEvent();
+        },
+    });
+
+    const timeout = () => {
+        return new Promise(resolve => {
+            t.step_timeout(resolve, 0);
+        });
+    };
+
+    const eventWatcher = new EventWatcher(t, window, "error", timeout);
+    const errorPromise = eventWatcher.wait_for("error");
+
+    target.dispatchEvent(new Event(type));
+
+    const event = await errorPromise;
+    assert_equals(calls, 1, "handleEvent property was not looked up");
+    throw event.error;
+};
+
+promise_test(t => {
+    const error = { name: "test" };
+
+    return promise_rejects_exactly(t, error,
+        uncaught_error_test(t, () => { throw error; }));
+}, "rethrows errors when getting `handleEvent`");
+
+promise_test(t => {
+    return promise_rejects_js(t, TypeError, uncaught_error_test(t, () => null));
+}, "throws if `handleEvent` is falsy and not callable");
+
+promise_test(t => {
+    return promise_rejects_js(t, TypeError, uncaught_error_test(t, () => 42));
+}, "throws if `handleEvent` is thruthy and not callable");
+</script>