add_task(async function() {
  await new Promise(resolve => waitForFocus(resolve, window));

  const kPageURL = "http://example.org/browser/editor/libeditor/tests/bug629172.html";
  await BrowserTestUtils.withNewTab({
    gBrowser,
    url: kPageURL
  }, async function(aBrowser) {
    await ContentTask.spawn(aBrowser, {}, async function() {
      var window = content.window.wrappedJSObject;
      var document = window.document;

      // Note: Using the with keyword, we would have been able to write this as:
      //
      // with (window) {
      //   Screenshots = {};
      //   // so on
      // }
      //
      // However, browser-chrome tests are somehow forced to run in strict mode,
      // which doesn't permit the usage of the with keyword, turning the following
      // into the ugliest test you've ever seen.  :(
      var LTRRef = document.getElementById("ltr-ref");
      var RTLRef = document.getElementById("rtl-ref");
      window.Screenshots = {};

      // generate the reference screenshots
      LTRRef.style.display = "";
      document.body.clientWidth;
      window.Screenshots.ltr = window.snapshotWindow(window);
      LTRRef.remove();
      RTLRef.style.display = "";
      document.body.clientWidth;
      window.Screenshots.rtl = window.snapshotWindow(window);
      RTLRef.remove();
      window.Screenshots.get = function(dir) {
        return this[dir];
      };
    });

    function simulateCtrlShiftX(aBrowser) {
      // In e10s, the keypress event will be dispatched to the content process,
      // but in non-e10s it is handled by the browser UI code and hence won't
      // reach the web page.  As a result, we need to observe the event in
      // the content process only in e10s mode.
      if (gMultiProcessBrowser) {
        return EventUtils.synthesizeAndWaitKey("x", {accelKey: true, shiftKey: true});
      }
      EventUtils.synthesizeKey("x", {accelKey: true, shiftKey: true});
      return Promise.resolve();
    }

    async function testDirection(initialDir, aBrowser) {
      await ContentTask.spawn(aBrowser, {initialDir}, function({initialDir}) {
        var window = content.window.wrappedJSObject;
        var document = window.document;

        var t = window.t = document.createElement("textarea");
        t.setAttribute("dir", initialDir);
        t.value = "test.";
        window.inputEventCount = 0;
        t.oninput = function() { window.inputEventCount++; };
        document.getElementById("content").appendChild(t);
        document.body.clientWidth;
        var s1 = window.snapshotWindow(window);
        window.ok = ok; // for assertSnapshots
        window.
          assertSnapshots(s1, window.Screenshots.get(initialDir), true,
                          /* fuzz = */ null,
                          "Textarea before switching the direction from " +
                            initialDir,
                          "Reference " + initialDir + " textarea");
        t.focus();
        is(window.inputEventCount, 0, "input event count must be 0 before");
      });
      await simulateCtrlShiftX(aBrowser);
      await ContentTask.spawn(aBrowser, {initialDir}, function({initialDir}) {
        var window = content.window.wrappedJSObject;
        var expectedDir = initialDir == "ltr" ? "rtl" : "ltr"
        is(window.t.getAttribute("dir"), expectedDir,
           "The dir attribute must be correctly updated");
        is(window.inputEventCount, 1, "input event count must be 1 after");
        window.t.blur();
        var s2 = window.snapshotWindow(window);
        window.ok = ok; // for assertSnapshots
        window.
          assertSnapshots(s2, window.Screenshots.get(expectedDir), true,
                        /* fuzz = */ null,
                          "Textarea after switching the direction from " +
                            initialDir,
                          "Reference " + expectedDir + " textarea");
        window.t.focus();
        is(window.inputEventCount, 1, "input event count must be 1 before");
      });
      await simulateCtrlShiftX(aBrowser);
      await ContentTask.spawn(aBrowser, {initialDir}, function({initialDir}) {
        var window = content.window.wrappedJSObject;

        is(window.inputEventCount, 2, "input event count must be 2 after");
        is(window.t.getAttribute("dir"), initialDir == "ltr" ? "ltr" : "rtl", "The dir attribute must be correctly updated");
        window.t.blur();
        var s3 = window.snapshotWindow(window);
        window.ok = ok; // for assertSnapshots
        window.
          assertSnapshots(s3, window.Screenshots.get(initialDir), true,
                          /* fuzz = */ null,
                          "Textarea after switching back the direction to " +
                            initialDir,
                          "Reference " + initialDir + " textarea");
        window.t.remove();
      });
    }

    await testDirection("ltr", aBrowser);
    await testDirection("rtl", aBrowser);
  });
});
