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test(performance-timer): reduce flakiness of tests involving actual sleeps (round 2) #4896

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Merged
dbjorge merged 1 commit into from
Sep 30, 2025
+7 −4
Merged

test(performance-timer): reduce flakiness of tests involving actual sleeps (round 2) #4896

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11 changes: 7 additions & 4 deletions test/core/utils/performance-timer.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,9 @@ describe('performance timer', () => {
let messages = [];
const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));

// Browser sleeps can slop a bit (in either direction) to sync with other work on the main thread.
const ANIMATION_FRAME_TOLERANCE_MS = 17; // Math.ceil(time per frame at 60Hz)

const getNumber = msg => {
const match = msg.match(/([0-9.]+)ms/);
return match ? parseFloat(match[1]) : 0;
Expand Down Expand Up @@ -63,7 +66,7 @@ describe('performance timer', () => {
assert.equal(messages.length, 1);
const actual = getNumber(messages[0]);

assert.isAtLeast(actual, 100);
assert.isAtLeast(actual, 100 - ANIMATION_FRAME_TOLERANCE_MS);

// The actual value might be significantly >100ms in a browser, especially on a
// CI agent with a slow CPU, but should be consistent with performance.now()
Expand Down Expand Up @@ -171,7 +174,7 @@ describe('performance timer', () => {
const actual = performanceTimer.timeElapsed();
const timestampPostTimeElapsed = performance.now();

assert.isAtLeast(actual, 100);
assert.isAtLeast(actual, 100 - ANIMATION_FRAME_TOLERANCE_MS);
const maxExpected = timestampPostTimeElapsed - timestampPreStart;
const minExpected = timestampPreTimeElapsed - timestampPostStart;
assert.isAtLeast(actual, minExpected);
Expand All @@ -189,7 +192,7 @@ describe('performance timer', () => {
const actual = performanceTimer.timeElapsed();
const timestampPostTimeElapsed = performance.now();

assert.isAtLeast(actual, 100);
assert.isAtLeast(actual, 100 - ANIMATION_FRAME_TOLERANCE_MS);
const maxExpected = timestampPostTimeElapsed - timestampPreStart;
const minExpected = timestampPreTimeElapsed - timestampPostStart;
assert.isAtLeast(actual, minExpected);
Expand All @@ -208,7 +211,7 @@ describe('performance timer', () => {
const actual = performanceTimer.timeElapsed();
const timestampPostTimeElapsed = performance.now();

assert.isAtLeast(actual, 100);
assert.isAtLeast(actual, 100 - ANIMATION_FRAME_TOLERANCE_MS);
const maxExpected = timestampPostTimeElapsed - timestampPreStart;
const minExpected = timestampPreTimeElapsed - timestampPostStart;
assert.isAtLeast(actual, minExpected);
Expand Down