new file mode 100644
--- /dev/null
+++ b/toolkit/modules/tests/xpcshell/test_EventEmitter.js
@@ -0,0 +1,162 @@
+/* Any copyright do_check_eq dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+var {classes: Cc, interfaces: Ci, results: Cr, utils: Cu, manager: Cm} = Components;
+
+Cu.import("resource://gre/modules/EventEmitter.jsm");
+
+add_task(function* test_extractFiles() {
+ testEmitter(new EventEmitter());
+
+ let decorated = {};
+ EventEmitter.decorate(decorated);
+ testEmitter(decorated);
+
+ yield testPromise();
+})
+
+
+function testEmitter(emitter) {
+ do_check_true(emitter, "We have an event emitter");
+
+ let beenHere1 = false;
+ let beenHere2 = false;
+
+ emitter.on("next", next);
+ emitter.emit("next", "abc", "def");
+
+ function next(eventName, str1, str2) {
+ do_check_eq(eventName, "next", "Got event");
+ do_check_eq(str1, "abc", "Argument 1 do_check_eq correct");
+ do_check_eq(str2, "def", "Argument 2 do_check_eq correct");
+
+ do_check_false(beenHere1, "first time in next callback");
+ beenHere1 = true;
+
+ emitter.off("next", next);
+
+ emitter.emit("next");
+
+ emitter.once("onlyonce", onlyOnce);
+
+ emitter.emit("onlyonce");
+ emitter.emit("onlyonce");
+ }
+
+ function onlyOnce() {
+ do_check_true(!beenHere2, "\"once\" listener has been called once");
+ beenHere2 = true;
+ emitter.emit("onlyonce");
+
+ testThrowingExceptionInListener();
+ }
+
+ function testThrowingExceptionInListener() {
+ function throwListener() {
+ emitter.off("throw-exception");
+ throw {
+ toString: () => "foo",
+ stack: "bar",
+ };
+ }
+
+ emitter.on("throw-exception", throwListener);
+ emitter.emit("throw-exception");
+
+ killItWhileEmitting();
+ }
+
+ function killItWhileEmitting() {
+ function c1() {
+ do_check_true(true, "c1 called");
+ }
+ function c2() {
+ do_check_true(true, "c2 called");
+ emitter.off("tick", c3);
+ }
+ function c3() {
+ do_check_true(false, "c3 should not be called");
+ }
+ function c4() {
+ do_check_true(true, "c4 called");
+ }
+
+ emitter.on("tick", c1);
+ emitter.on("tick", c2);
+ emitter.on("tick", c3);
+ emitter.on("tick", c4);
+
+ emitter.emit("tick");
+
+ offAfterOnce();
+ }
+
+ function offAfterOnce() {
+ let enteredC1 = false;
+
+ function c1() {
+ enteredC1 = true;
+ }
+
+ emitter.once("oao", c1);
+ emitter.off("oao", c1);
+
+ emitter.emit("oao");
+
+ do_check_false(enteredC1, "c1 should not be called");
+ }
+}
+
+function* testPromise() {
+ let emitter = new EventEmitter();
+ let p = emitter.once("thing");
+
+ // Check that the promise do_check_eq only resolved once event though we
+ // emit("thing") more than once
+ let firstCallbackCalled = false;
+ let check1 = p.then(arg => {
+ do_check_eq(firstCallbackCalled, false, "first callback called only once");
+ firstCallbackCalled = true;
+ do_check_eq(arg, "happened", "correct arg in promise");
+ return "rval from c1";
+ });
+
+ emitter.emit("thing", "happened", "ignored");
+
+ // Check that the promise do_check_eq resolved asynchronously
+ let secondCallbackCalled = false;
+ let check2 = p.then(arg => {
+ do_check_true(true, "second callback called");
+ do_check_eq(arg, "happened", "correct arg in promise");
+ secondCallbackCalled = true;
+ do_check_eq(arg, "happened", "correct arg in promise (a second time)");
+ return "rval from c2";
+ });
+
+ // Shouldn't call any of the above listeners
+ emitter.emit("thing", "trashinate");
+
+ // Check that we can still separate events with different names
+ // and that it works with no parameters
+ let pfoo = emitter.once("foo");
+ let pbar = emitter.once("bar");
+
+ let check3 = pfoo.then(arg => {
+ do_check_eq(arg, undefined, "no arg for foo event");
+ return "rval from c3";
+ });
+
+ pbar.then(() => {
+ do_check_true(false, "pbar should not be called");
+ });
+
+ emitter.emit("foo");
+
+ do_check_eq(secondCallbackCalled, false, "second callback not called yet");
+
+ return Promise.all([ check1, check2, check3 ]).then(args => {
+ do_check_eq(args[0], "rval from c1", "callback 1 done good");
+ do_check_eq(args[1], "rval from c2", "callback 2 done good");
+ do_check_eq(args[2], "rval from c3", "callback 3 done good");
+ });
+}