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Test Info:
"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.
*
* 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 opening a new tab that will
* cause the existing tabs to squeeze smaller.
*/
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"]],
});
// Compute the number of tabs we can put into the strip without
// overflowing, and remove one, so that we can create
// TAB_COUNT_FOR_SQUEEE tabs, and then one more, which should
// cause the tab to squeeze to a smaller size rather than overflow.
const TAB_COUNT_FOR_SQUEEZE = computeMaxTabCount() - 1;
await createTabs(TAB_COUNT_FOR_SQUEEZE);
gURLBar.focus();
let tabStripRect =
gBrowser.tabContainer.arrowScrollbox.getBoundingClientRect();
let textBoxRect = gURLBar
.querySelector("moz-input-box")
.getBoundingClientRect();
await withPerfObserver(
async function () {
let switchDone = BrowserTestUtils.waitForEvent(window, "TabSwitchDone");
BrowserCommands.openTab();
await BrowserTestUtils.waitForEvent(
gBrowser.selectedTab,
"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)
)
)
),
exceptions: [
{
name: "the urlbar placeolder moves up and down by a few pixels",
condition: r =>
r.x1 >= textBoxRect.left &&
r.x2 <= textBoxRect.right &&
r.y1 >= textBoxRect.top &&
r.y2 <= textBoxRect.bottom,
},
],
},
}
);
await removeAllButFirstTab();
});