Bug 173946 – REGRESSION Layout Test media/modern-media-controls/fullscreen-support/fullscreen-support-press.html is flaky

• Component: New Bugs
• Status: NEW

[Matt Lewis]

media/modern-media-controls/fullscreen-support/fullscreen-support-press.html is a flaky failure on Sierra WK2 Debug and has most recently had an extended timeout according to the Flakiness Dashboard.
https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=media%2Fmodern-media-controls%2Ffullscreen-support%2Ffullscreen-support-press.html

The Failures started after a re-baslining of the test and adjusted expectations. It seems these were primarily aimed at iOS Simulator.
https://trac.webkit.org/changeset/218231/webkit
The failures however, have inconsistent Diffs.

Currently the test had a timeout that lasted 101 seconds:
https://build.webkit.org/builders/Apple%20Sierra%20Debug%20WK2%20(Tests)/builds/1787
https://build.webkit.org/results/Apple%20Sierra%20Debug%20WK2%20(Tests)/r218886%20(1787)/results.html

Diff for timeout:
--- /Volumes/Data/slave/sierra-debug-tests-wk2/build/layout-test-results/media/modern-media-controls/fullscreen-support/fullscreen-support-press-expected.txt
+++ /Volumes/Data/slave/sierra-debug-tests-wk2/build/layout-test-results/media/modern-media-controls/fullscreen-support/fullscreen-support-press-actual.txt
@@ -1,10 +1,5 @@
-Testing the FullscreenSupport behavior when clicking the fullscreen button.
+#PID UNRESPONSIVE - com.apple.WebKit.WebContent.Development (pid 20338)
+FAIL: Timed out waiting for notifyDone to be called
 
-On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
-
-
-PASS media.webkitDisplayingFullscreen is true
-PASS successfullyParsed is true
-
-TEST COMPLETE
-
+#EOF
+#EOF

[Antoine Quint]

I can get some failures locally with this command:

$ run-webkit-tests --debug -g --iterations=500 --run-singly --exit-after-n-failures=1 media/modern-media-controls/fullscreen-support/fullscreen-support-press.html

Investigating…

[Radar WebKit Bug Importer]

<rdar://problem/33122070>

[Matt Lewis]

Marked test as flaky on macOS WK2 Debug:
https://trac.webkit.org/changeset/220375/webkit