forked from mirrors/gecko-dev
53 lines
1.9 KiB
JavaScript
53 lines
1.9 KiB
JavaScript
/* Any copyright is dedicated to the Public Domain.
|
|
http://creativecommons.org/publicdomain/zero/1.0/ */
|
|
|
|
"use strict";
|
|
|
|
/**
|
|
* WHOA THERE: We should never be adding new things to EXPECTED_REFLOWS. This
|
|
* is a whitelist that should slowly go away as we improve the performance of
|
|
* the front-end. Instead of adding more reflows to the whitelist, you should
|
|
* be modifying your code to avoid the reflow.
|
|
*
|
|
* See https://developer.mozilla.org/en-US/Firefox/Performance_best_practices_for_Firefox_fe_engineers
|
|
* for tips on how to do that.
|
|
*/
|
|
const EXPECTED_REFLOWS = [
|
|
/**
|
|
* Nothing here! Please don't add anything new!
|
|
*/
|
|
];
|
|
|
|
/*
|
|
* This test ensures that there are no unexpected
|
|
* uninterruptible reflows when switching between two
|
|
* tabs that are both fully visible.
|
|
*/
|
|
add_task(async function() {
|
|
await ensureNoPreloadedBrowser();
|
|
|
|
// At the time of writing, there are no reflows on simple tab switching.
|
|
// Mochitest will fail if we have no assertions, so we add one here
|
|
// to make sure nobody adds any new ones.
|
|
Assert.equal(EXPECTED_REFLOWS.length, 0,
|
|
"We shouldn't have added any new expected reflows.");
|
|
|
|
// Because the tab strip is a scrollable frame, we can't use the
|
|
// default dirtying function from withReflowObserver and reliably
|
|
// get reflows for the strip. Instead, we provide a node that's
|
|
// already in the scrollable frame to dirty - in this case, the
|
|
// original tab.
|
|
let origTab = gBrowser.selectedTab;
|
|
|
|
let firstSwitchDone = BrowserTestUtils.waitForEvent(window, "TabSwitchDone");
|
|
let otherTab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
|
|
await firstSwitchDone;
|
|
|
|
await withReflowObserver(async function() {
|
|
let switchDone = BrowserTestUtils.waitForEvent(window, "TabSwitchDone");
|
|
gBrowser.selectedTab = origTab;
|
|
await switchDone;
|
|
}, EXPECTED_REFLOWS, window, origTab);
|
|
|
|
await BrowserTestUtils.removeTab(otherTab);
|
|
});
|