1 files changed, 162 insertions, 0 deletions
diff --git a/toolkit/modules/tests/xpcshell/test_EventEmitter.js b/toolkit/modules/tests/xpcshell/test_EventEmitter.js
new file mode 100644
index 0000000000..376246f559
--- /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/ */
+
+const { EventEmitter } = ChromeUtils.importESModule(
+  "resource://gre/modules/EventEmitter.sys.mjs"
+);
+
+add_task(async function test_extractFiles() {
+  testEmitter(new EventEmitter());
+
+  let decorated = {};
+  EventEmitter.decorate(decorated);
+  testEmitter(decorated);
+
+  await testPromise();
+});
+
+function testEmitter(emitter) {
+  Assert.ok(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) {
+    Assert.equal(eventName, "next", "Got event");
+    Assert.equal(str1, "abc", "Argument 1 do_check_eq correct");
+    Assert.equal(str2, "def", "Argument 2 do_check_eq correct");
+
+    Assert.ok(!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() {
+    Assert.ok(!beenHere2, '"once" listener has been called once');
+    beenHere2 = true;
+    emitter.emit("onlyonce");
+
+    testThrowingExceptionInListener();
+  }
+
+  function testThrowingExceptionInListener() {
+    function throwListener() {
+      emitter.off("throw-exception");
+      // eslint-disable-next-line no-throw-literal
+      throw {
+        toString: () => "foo",
+        stack: "bar",
+      };
+    }
+
+    emitter.on("throw-exception", throwListener);
+    emitter.emit("throw-exception");
+
+    killItWhileEmitting();
+  }
+
+  function killItWhileEmitting() {
+    function c1() {
+      Assert.ok(true, "c1 called");
+    }
+    function c2() {
+      Assert.ok(true, "c2 called");
+      emitter.off("tick", c3);
+    }
+    function c3() {
+      Assert.ok(false, "c3 should not be called");
+    }
+    function c4() {
+      Assert.ok(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");
+
+    Assert.ok(!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 => {
+    Assert.equal(firstCallbackCalled, false, "first callback called only once");
+    firstCallbackCalled = true;
+    Assert.equal(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 => {
+    Assert.ok(true, "second callback called");
+    Assert.equal(arg, "happened", "correct arg in promise");
+    secondCallbackCalled = true;
+    Assert.equal(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 => {
+    Assert.equal(arg, undefined, "no arg for foo event");
+    return "rval from c3";
+  });
+
+  pbar.then(() => {
+    Assert.ok(false, "pbar should not be called");
+  });
+
+  emitter.emit("foo");
+
+  Assert.equal(secondCallbackCalled, false, "second callback not called yet");
+
+  return Promise.all([check1, check2, check3]).then(args => {
+    Assert.equal(args[0], "rval from c1", "callback 1 done good");
+    Assert.equal(args[1], "rval from c2", "callback 2 done good");
+    Assert.equal(args[2], "rval from c3", "callback 3 done good");
+  });
+}