Bug 158480 – Investigate cause of flakiness in http/tests/websocket/tests/hybi/upgrade-simple-ws.html test

• Status: RESOLVED
• Resolution: FIXED
• Component: WebCore Misc.

[Brent Fulgham]

Investigate the cause of flakiness in the WebSocket upgrade code path:

Test: http/tests/websocket/tests/hybi/upgrade-simple-ws.html

The test is a flaky failure on El Capitan and iOS simulator. It is failing and crashing on Windows.

Recent failure:
<https://build.webkit.org/builders/Apple%20El%20Capitan%20Debug%20WK1%20(Tests)/builds/5721>

Flakiness dashboard:
<https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=http%2Ftests%2Fwebsocket%2Ftests%2Fhybi%2Fupgrade-simple-ws.html>

--- /Volumes/Data/slave/ios-simulator-9-release-tests-wk2/build/layout-test-results/http/tests/websocket/tests/hybi/upgrade-simple-ws-expected.txt
+++ /Volumes/Data/slave/ios-simulator-9-release-tests-wk2/build/layout-test-results/http/tests/websocket/tests/hybi/upgrade-simple-ws-actual.txt
@@ -4,8 +4,4 @@
 
 Created a socket to 'wss://127.0.0.1:9323/websocket/tests/hybi/simple'; readyState 0.
 The 'ws' protocol should be upgraded to 'wss'. If this happens, we will connect properly and the test will succeed.
-Connected; readyState 1
-Resolved URL: wss://127.0.0.1:9323/websocket/tests/hybi/simple
-Received: 'Hello from Simple WSH.'; readyState 1
-Closed; readyState 3.

[Brent Fulgham]

About 1 in 1000 times I can get the test to time out, but I'm not seeing other failures. Since this test relies on an external Python server to do its work, we might be running into some flakiness with that dependency.

[Alexey Proskuryakov]

Will it reproduce when forced to run many copies of itself in parallel?

[Ahmad Saleem]

This seems to be skipped for all platform: https://searchfox.org/wubkat/rev/6ab17cf692e2176ae76cd00a44e48fb608faaf46/LayoutTests/TestExpectations#2536

Should we try to reenable it and run it again since AppleWin port is gone? or at least enable it for the platform where it is working?

[Alexey Proskuryakov]

Good idea! If you post a PR and modify the test in some minor way, stress test EWS should execute it with multiple iterations.

[Ahmad Saleem]

Just for an update, I tried this in PR and it seems that this test definitely fails across all platform - https://github.com/WebKit/WebKit/pull/21887

[Diego Pino]

Pull request: https://github.com/WebKit/WebKit/pull/49715

[EWS]

Committed 299057@main (f4cdff05b82d): <https://commits.webkit.org/299057@main>

Reviewed commits have been landed. Closing PR #49715 and removing active labels.

[Radar WebKit Bug Importer]

<rdar://problem/158954229>