browser_dispatchKeyEvent_race.js

Enable keyboard shortcuts

/* Any copyright is dedicated to the Public Domain.

 * http://creativecommons.org/publicdomain/zero/1.0/ */

"use strict";

// Here we test that the `dispatchKeyEvent` API resolves after all the synchronous event

// handlers from the content page have been flushed.

//

// Say the content page has an event handler such as:

//

//   el.addEventListener("keyup", () => {

//     doSomeVeryLongProcessing(); // <- takes a long time but is synchronous!

//     window.myVariable = "newValue";

//   });

//

// And imagine this is tested via:

//

//   await Input.dispatchKeyEvent(...);

//   const myVariable = await Runtime.evaluate({ expression: "window.myVariable" });

//   equals(myVariable, "newValue");

//

// In order for this to work, we need to be sure that `await Input.dispatchKeyEvent`

// resolves only after the content page flushed the event handlers (and

// `window.myVariable = "newValue"` was executed).

//

// This can be racy because Input.dispatchKeyEvent and window.myVariable = "newValue" run

// in different processes.

const PAGE_URL =

  "https://example.com/browser/remote/cdp/test/browser/input/doc_dispatchKeyEvent_race.html";

add_task(async function ({ client }) {

  await loadURL(PAGE_URL);

  const { Input, Runtime } = client;

  // Need an enabled Runtime domain to run evaluate.

  info("Enable the Runtime domain");

  await Runtime.enable();

  const { context } = await Runtime.executionContextCreated();

  info("Focus the input on the page");

  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {

    const input = content.document.querySelector("input");

    input.focus();

    is(input, content.document.activeElement, "Input should be focused");

});

  // See doc_input_dispatchKeyEvent_race.html

  // The page listens to `input` events to update a property on window.

  // We will check that the value is updated as soon dispatchKeyEvent has resolved.

  await checkWindowTestValue("initial-value", context.id, Runtime);

  info("Write 'hhhhhh' ('h' times 6)");

  for (let i = 0; i < 6; i++) {

    await dispatchKeyEvent(Input, "h", 72, "keyDown");

    await dispatchKeyEvent(Input, "h", 72, "keyUp");

  await checkWindowTestValue("hhhhhh", context.id, Runtime);

  info("Write 'aaaaaa' with 6 consecutive keydown and one keyup");

  await Promise.all([

    dispatchKeyEvent(Input, "a", 65, "keyDown"),

    dispatchKeyEvent(Input, "a", 65, "keyDown"),

    dispatchKeyEvent(Input, "a", 65, "keyDown"),

    dispatchKeyEvent(Input, "a", 65, "keyDown"),

    dispatchKeyEvent(Input, "a", 65, "keyDown"),

    dispatchKeyEvent(Input, "a", 65, "keyDown"),

]);

  await dispatchKeyEvent(Input, "a", 65, "keyUp");

  await checkWindowTestValue("hhhhhhaaaaaa", context.id, Runtime);

});

function dispatchKeyEvent(Input, key, keyCode, type, modifiers = 0) {

  info(`Send ${type} for key ${key}`);

  return Input.dispatchKeyEvent({

    type,

    modifiers,

    windowsVirtualKeyCode: keyCode,

    key,

});

async function checkWindowTestValue(expected, contextId, Runtime) {

  info("Retrieve the value of `window.testValue` in the test page");

  const { result } = await Runtime.evaluate({

    contextId,

    expression: "window.testValue",

});

  is(result.value, expected, "Content window test value is correct");