1 files changed, 181 insertions, 0 deletions
diff --git a/devtools/shared/tests/xpcshell/test_eventemitter_abort_controller.js b/devtools/shared/tests/xpcshell/test_eventemitter_abort_controller.js
new file mode 100644
index 0000000000..9a35ce1f98
--- /dev/null
+++ b/devtools/shared/tests/xpcshell/test_eventemitter_abort_controller.js
@@ -0,0 +1,181 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const EventEmitter = require("resource://devtools/shared/event-emitter.js");
+
+add_task(function testAbortSingleListener() {
+  // Test a simple case with AbortController
+  info("Create an EventEmitter");
+  const emitter = new EventEmitter();
+  const abortController = new AbortController();
+  const { signal } = abortController;
+
+  info("Setup an event listener on test-event, controlled by an AbortSignal");
+  let eventsReceived = 0;
+  emitter.on("test-event", () => eventsReceived++, { signal });
+
+  info("Emit test-event");
+  emitter.emit("test-event");
+  equal(eventsReceived, 1, "We received one event, as expected");
+
+  info("Abort the AbortController…");
+  abortController.abort();
+  info("… and emit test-event again");
+  emitter.emit("test-event");
+  equal(eventsReceived, 1, "We didn't receive new event after aborting");
+});
+
+add_task(function testAbortSingleListenerOnce() {
+  // Test a simple case with AbortController and once
+  info("Create an EventEmitter");
+  const emitter = new EventEmitter();
+  const abortController = new AbortController();
+  const { signal } = abortController;
+
+  info("Setup an event listener on test-event, controlled by an AbortSignal");
+  let eventReceived = false;
+  emitter.once(
+    "test-event",
+    () => {
+      eventReceived = true;
+    },
+    { signal }
+  );
+
+  info("Abort the AbortController…");
+  abortController.abort();
+  info("… and emit test-event");
+  emitter.emit("test-event");
+  equal(eventReceived, false, "We didn't receive the event after aborting");
+});
+
+add_task(function testAbortMultipleListener() {
+  // Test aborting multiple event listeners with one call to abort
+  info("Create an EventEmitter");
+  const emitter = new EventEmitter();
+  const abortController = new AbortController();
+  const { signal } = abortController;
+
+  info("Setup 3 event listeners controlled by an AbortSignal");
+  let eventsReceived = 0;
+  emitter.on("test-event", () => eventsReceived++, { signal });
+  emitter.on("test-event", () => eventsReceived++, { signal });
+  emitter.on("other-test-event", () => eventsReceived++, { signal });
+
+  info("Emit test-event and other-test-event");
+  emitter.emit("test-event");
+  emitter.emit("other-test-event");
+  equal(eventsReceived, 3, "We received 3 events, as expected");
+
+  info("Abort the AbortController…");
+  abortController.abort();
+  info("… and emit events again");
+  emitter.emit("test-event");
+  emitter.emit("other-test-event");
+  equal(eventsReceived, 3, "We didn't receive new event after aborting");
+});
+
+add_task(function testAbortMultipleEmitter() {
+  // Test aborting multiple event listeners on different emitters with one call to abort
+  info("Create 2 EventEmitter");
+  const emitter1 = new EventEmitter();
+  const emitter2 = new EventEmitter();
+  const abortController = new AbortController();
+  const { signal } = abortController;
+
+  info("Setup 2 event listeners on test-event, controlled by an AbortSignal");
+  let eventsReceived = 0;
+  emitter1.on("test-event", () => eventsReceived++, { signal });
+  emitter2.on("other-test-event", () => eventsReceived++, { signal });
+
+  info("Emit test-event and other-test-event");
+  emitter1.emit("test-event");
+  emitter2.emit("other-test-event");
+  equal(eventsReceived, 2, "We received 2 events, as expected");
+
+  info("Abort the AbortController…");
+  abortController.abort();
+  info("… and emit events again");
+  emitter1.emit("test-event");
+  emitter2.emit("other-test-event");
+  equal(eventsReceived, 2, "We didn't receive new event after aborting");
+});
+
+add_task(function testAbortBeforeEmitting() {
+  // Check that aborting before emitting does unregister the event listener
+  info("Create an EventEmitter");
+  const emitter = new EventEmitter();
+  const abortController = new AbortController();
+  const { signal } = abortController;
+
+  info("Setup an event listener on test-event, controlled by an AbortSignal");
+  let eventsReceived = 0;
+  emitter.on("test-event", () => eventsReceived++, { signal });
+
+  info("Abort the AbortController…");
+  abortController.abort();
+
+  info("… and emit test-event");
+  emitter.emit("test-event");
+  equal(eventsReceived, 0, "We didn't receive any event");
+});
+
+add_task(function testAbortBeforeSettingListener() {
+  // Check that aborting before creating the event listener won't register it
+  info("Create an EventEmitter");
+  const emitter = new EventEmitter();
+
+  info("Create an AbortController and abort it immediately");
+  const abortController = new AbortController();
+  const { signal } = abortController;
+  abortController.abort();
+
+  info(
+    "Setup an event listener on test-event, controlled by the aborted AbortSignal"
+  );
+  let eventsReceived = 0;
+  const off = emitter.on("test-event", () => eventsReceived++, { signal });
+
+  info("Emit test-event");
+  emitter.emit("test-event");
+  equal(eventsReceived, 0, "We didn't receive any event");
+
+  equal(typeof off, "function", "emitter.on still returned a function");
+  // check that calling off does not throw
+  off();
+});
+
+add_task(function testAbortAfterEventListenerIsRemoved() {
+  // Check that aborting after there's no more event listener does not throw
+  info("Create an EventEmitter");
+  const emitter = new EventEmitter();
+
+  const abortController = new AbortController();
+  const { signal } = abortController;
+
+  info(
+    "Setup an event listener on test-event, controlled by the aborted AbortSignal"
+  );
+  let eventsReceived = 0;
+  const off = emitter.on("test-event", () => eventsReceived++, { signal });
+
+  info("Emit test-event");
+  emitter.emit("test-event");
+  equal(eventsReceived, 1, "We received the expected event");
+
+  info("Remove the event listener with the function returned by `on`");
+  off();
+
+  info("Emit test-event a second time");
+  emitter.emit("test-event");
+  equal(
+    eventsReceived,
+    1,
+    "We didn't receive new event after removing the event listener"
+  );
+
+  info("Abort to check it doesn't throw");
+  abortController.abort();
+});