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"use strict";
/**
* WHOA THERE: We should never be adding new things to EXPECTED_REFLOWS.
* Instead of adding reflows to the list, you should be modifying your code to
* avoid the reflow.
*
* See https://firefox-source-docs.mozilla.org/performance/bestpractices.html
* 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 () {
// Force-enable tab animations
gReduceMotionOverride = false;
await ensureNoPreloadedBrowser();
await disableFxaBadge();
// The test starts on about:blank and opens an about:blank
// tab which triggers opening the toolbar since
// ensureNoPreloadedBrowser sets AboutNewTab.newTabURL to about:blank.
await SpecialPowers.pushPrefEnv({
set: [["browser.toolbars.bookmarks.visibility", "never"]],
});
// 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();
function isInTabStrip(r) {
return (
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 withPerfObserver(
async function () {
let switchDone = BrowserTestUtils.waitForEvent(window, "TabSwitchDone");
let tab = gBrowser.tabs[gBrowser.tabs.length - 1];
gBrowser.removeTab(tab, { animate: true });
await BrowserTestUtils.waitForEvent(tab, "TabAnimationEnd");
await switchDone;
},
{
expectedReflows: EXPECTED_REFLOWS,
frames: {
filter: rects => rects.filter(r => !isInTabStrip(r)),
},
}
);
await removeAllButFirstTab();
});
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