DOM: signal support for addEventListener()

Tests for whatwg/dom#919.

dom/events/AddEventListenerOptions-signal.any.js

@@ -0,0 +1,133 @@
+'use strict';
+
+test(function() {
+  let count = 0;
+  function handler() {
+    count++;
+  }
+  const et = new EventTarget();
+  const controller = new AbortController();
+  et.addEventListener('test', handler, { signal: controller.signal });
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 1, "Adding a signal still adds a listener");
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 2, "The listener was not added with the once flag");
+  controller.abort();
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 2, "Aborting on the controller removes the listener");
+  et.addEventListener('test', handler, { signal: controller.signal });
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 2, "Passing an aborted signal never adds the handler");
+}, "Passing an AbortSignal to addEventListener options should allow removing a listener");
+
+test(function() {
+  let count = 0;
+  function handler() {
+    count++;
+  }
+  const et = new EventTarget();
+  const controller = new AbortController();
+  et.addEventListener('test', handler, { signal: controller.signal });
+  et.removeEventListener('test', handler);
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 0, "The listener was still removed");
+}, "Passing an AbortSignal to addEventListener does not prevent removeEventListener");
+
+test(function() {
+  let count = 0;
+  function handler() {
+    count++;
+  }
+  const et = new EventTarget();
+  const controller = new AbortController();
+  et.addEventListener('test', handler, { signal: controller.signal, once: true });
+  controller.abort();
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 0, "The listener was still removed");
+}, "Passing an AbortSignal to addEventListener works with the once flag");
+
+test(function() {
+  let count = 0;
+  function handler() {
+    count++;
+  }
+  const et = new EventTarget();
+  const controller = new AbortController();
+  et.addEventListener('test', handler, { signal: controller.signal, once: true });
+  et.removeEventListener('test', handler);
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 0, "The listener was still removed");
+}, "Removing a once listener works with a passed signal");
+
+test(function() {
+  let count = 0;
+  function handler() {
+    count++;
+  }
+  const et = new EventTarget();
+  const controller = new AbortController();
+  et.addEventListener('first', handler, { signal: controller.signal, once: true });
+  et.addEventListener('second', handler, { signal: controller.signal, once: true });
+  controller.abort();
+  et.dispatchEvent(new Event('first'));
+  et.dispatchEvent(new Event('second'));
+  assert_equals(count, 0, "The listener was still removed");
+}, "Passing an AbortSignal to multiple listeners");
+
+test(function() {
+  let count = 0;
+  function handler() {
+    count++;
+  }
+  const et = new EventTarget();
+  const controller = new AbortController();
+  et.addEventListener('test', handler, { signal: controller.signal, capture: true });
+  controller.abort();
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 0, "The listener was still removed");
+}, "Passing an AbortSignal to addEventListener works with the capture flag");
+
+test(function() {
+  let count = 0;
+  function handler() {
+    count++;
+  }
+  const et = new EventTarget();
+  const controller = new AbortController();
+  et.addEventListener('test', () => {
+    controller.abort();
+  }, { signal: controller.signal });
+  et.addEventListener('test', handler, { signal: controller.signal });
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 0, "The listener was still removed");
+}, "Aborting from a listener does not call future listeners");
+
+test(function() {
+  let count = 0;
+  function handler() {
+    count++;
+  }
+  const et = new EventTarget();
+  const controller = new AbortController();
+  et.addEventListener('test', () => {
+    et.addEventListener('test', handler, { signal: controller.signal });
+    controller.abort();
+  }, { signal: controller.signal });
+  et.dispatchEvent(new Event('test'));
+  assert_equals(count, 0, "The listener was still removed");
+}, "Adding then aborting a listener in another listener does not call it");
+
+test(function() {
+  const et = new EventTarget();
+  const ac = new AbortController();
+  let count = 0;
+  et.addEventListener('foo', () => {
+    et.addEventListener('foo', () => {
+      count++;
+      if (count > 5) ac.abort();
+      et.dispatchEvent(new Event('foo'));
+    }, { signal: ac.signal });
+    et.dispatchEvent(new Event('foo'));
+  }, { once: true });
+  et.dispatchEvent(new Event('foo'));
+}, "Aborting from a nested listener should remove it");