Bug 208384

Summary:	[ Mac wk1 ] imported/w3c/web-platform-tests/requestidlecallback/callback-timeout-when-busy.html is flakey failing.
Product:	WebKit	Reporter:	Jason Lawrence <Lawrence.j>
Component:	Tools / Tests	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	webkit-bot-watchers-bugzilla, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Mac
OS:	macOS 10.15

Description Jason Lawrence 2020-02-28 11:26:10 PST

imported/w3c/web-platform-tests/requestidlecallback/callback-timeout-when-busy.html

Description:
This test is flaky failing on Mac wk1. It appears to flaky fail throughout the visible history.

History:
https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Frequestidlecallback%2Fcallback-timeout-when-busy.html&flavor=wk1&platform=mac&limit=50000

Diff:
--- /Volumes/Data/slave/mojave-debug-tests-wk1/build/layout-test-results/imported/w3c/web-platform-tests/requestidlecallback/callback-timeout-when-busy-expected.txt
+++ /Volumes/Data/slave/mojave-debug-tests-wk1/build/layout-test-results/imported/w3c/web-platform-tests/requestidlecallback/callback-timeout-when-busy-actual.txt
@@ -1,6 +1,6 @@
 Test of requestIdleCallback timeout behavior
 
 
-FAIL requestIdleCallback not scheduled when event loop is busy. assert_false: IdleDeadline.didTimeout MUST be false if requestIdleCallback wasn't scheduled due to a timeout expected false got true
+FAIL requestIdleCallback not scheduled when event loop is busy. assert_equals: Busy event loop should be finished by the time we get scheduled expected 0 but got 7
 FAIL requestIdleCallback scheduled with timeout when event loop is busy. assert_true: IdleDeadline.timeRemaining MUST be equal to zero if requestIdleCallback was scheduled due to a timeout expected true got false

Comment 1 Radar WebKit Bug Importer 2020-02-28 11:26:30 PST

<rdar://problem/59895884>

Comment 2 Jason Lawrence 2020-02-28 11:30:08 PST

I have marked this test as failing while the issue is investigated.
https://trac.webkit.org/changeset/257646/webkit

Comment 3 Jason Lawrence 2020-03-02 16:25:07 PST

I can reproduce this issue with  r257738 by running the command below.

run-webkit-tests --iterations 1000 --exit-after-n-failures 4 --force -1 imported/w3c/web-platform-tests/requestidlecallback/callback-timeout-when-busy.html --no-retry

[1/1000] imported/w3c/web-platform-tests/requestidlecallback/callback-timeout-when-busy.html failed unexpectedly (text diff)
                                                                                 
999 tests ran as expected, 1 didn't: