fune/browser/base/content/test/performance/browser_tabclose_grow.js
Victor Porof f9f5914039 Bug 1561435 - Format browser/base/, a=automatic-formatting
# ignore-this-changeset

Differential Revision: https://phabricator.services.mozilla.com/D36041

--HG--
extra : source : 96b3895a3b2aa2fcb064c85ec5857b7216884556
2019-07-05 09:48:57 +02:00

81 lines
2.8 KiB
JavaScript

"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 closing a tab that will
* cause the existing tabs to grow bigger.
*/
add_task(async function() {
await ensureNoPreloadedBrowser();
// At the time of writing, there are no reflows on tab closing with
// tab growth. 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."
);
// Compute the number of tabs we can put into the strip without
// overflowing. If we remove one of the tabs, we know that the
// remaining tabs will grow to fill the remaining space in the
// tabstrip.
const TAB_COUNT_FOR_GROWTH = computeMaxTabCount();
await createTabs(TAB_COUNT_FOR_GROWTH);
let lastTab = gBrowser.tabs[gBrowser.tabs.length - 1];
await BrowserTestUtils.switchTab(gBrowser, lastTab);
let tabStripRect = gBrowser.tabContainer.arrowScrollbox.getBoundingClientRect();
await withPerfObserver(
async function() {
let switchDone = BrowserTestUtils.waitForEvent(window, "TabSwitchDone");
let tab = gBrowser.tabs[gBrowser.tabs.length - 1];
gBrowser.removeTab(tab, { animate: true, byMouse: true });
await BrowserTestUtils.waitForEvent(tab, "TabAnimationEnd");
await switchDone;
},
{
expectedReflows: EXPECTED_REFLOWS,
frames: {
filter: rects =>
rects.filter(
r =>
!// We expect plenty of changed rects within the tab strip.
(
r.y1 >= tabStripRect.top &&
r.y2 <= tabStripRect.bottom &&
r.x1 >= tabStripRect.left &&
r.x2 <= tabStripRect.right &&
// It would make sense for each rect to have a width smaller than
// a tab (ie. tabstrip.width / tabcount), but tabs are small enough
// that they sometimes get reported in the same rect.
// So we accept up to the width of n-1 tabs.
r.w <=
(gBrowser.tabs.length - 1) *
Math.ceil(tabStripRect.width / gBrowser.tabs.length)
)
),
},
}
);
await removeAllButFirstTab();
});