LayoutTest media/modern-media-controls/media-controller/media-controller-auto-hide-mouse-enter-over-controls-bar.html is a flaky failure

• Component: New Bugs
• Status: REOPENED ---

[Ryan Haddad]

LayoutTest media/modern-media-controls/media-controller/media-controller-auto-hide-mouse-enter-over-controls-bar.html is a flaky failure

https://build.webkit.org/results/Apple%20Sierra%20Release%20WK2%20(Tests)/r210992%20(2866)/results.html

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=media%2Fmodern-media-controls%2Fmedia-controller%2Fmedia-controller-auto-hide-mouse-enter-over-controls-bar.html

--- /Volumes/Data/slave/sierra-release-tests-wk2/build/layout-test-results/media/modern-media-controls/media-controller/media-controller-auto-hide-mouse-enter-over-controls-bar-expected.txt
+++ /Volumes/Data/slave/sierra-release-tests-wk2/build/layout-test-results/media/modern-media-controls/media-controller/media-controller-auto-hide-mouse-enter-over-controls-bar-actual.txt
@@ -7,7 +7,7 @@
 PASS controlsBar.classList.contains('faded') is false
 
 Auto-hide timer has elapsed, controls bar should be faded.
-PASS controlsBar.classList.contains('faded') is true
+FAIL controlsBar.classList.contains('faded') should be true. Was false.
 
 Mouse moved over the media, controls bar should be visible.
 PASS controlsBar.classList.contains('faded') is false

[Ryan Haddad]

Marked test as flaky in http://trac.webkit.org/projects/webkit/changeset/211000

[Antoine Quint]

This is tricky because this test, and a host of others, is timing-sensitive by design since it's testing the auto-hide timer. The test checks as close as possible to the auto-hide delay that the controls are still visible, and then again as soon as possible after the auto-hide delay has elapsed to check that the controls are no longer visible. So in certain cases, probably where the system is under pressure and timers run late, we get in cases where the check prior to the timer firing fails because we've actually run past auto-hide delay. We're going to have to find a different way to test this.

[Antoine Quint]

Committed r211424: <http://trac.webkit.org/changeset/211424>

[Ryan Haddad]

Just saw this fail again:
https://build.webkit.org/results/Apple%20Sierra%20Release%20WK1%20(Tests)/r211438%20(3272)/results.html

[Alexey Proskuryakov]

This test has 300ms timeouts. This never works in layout tests - due to scheduler operation, a process may not get any time for longer than than.

[Ryan Haddad]

Marked as flaky again in http://trac.webkit.org/projects/webkit/changeset/211447

[Antoine Quint]

(In reply to comment #5)
> This test has 300ms timeouts. This never works in layout tests - due to
> scheduler operation, a process may not get any time for longer than than.

What do you mean by "never works in layout tests"? Clearly it does the majority of the time.