Bug 231241

Summary: [webkitpy] The actual results reported for a flaky tests shouldn't include the expectation
Product: WebKit Reporter: Carlos Alberto Lopez Perez <clopez>
Component: Tools / TestsAssignee: Carlos Alberto Lopez Perez <clopez>
Severity: Normal CC: aakash_jain, ap, dewei_zhu, ews-watchlist, glenn, jbedard, ryanhaddad, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=231790
Description Flags
Patch none

Description Carlos Alberto Lopez Perez 2021-10-05 11:12:45 PDT
This is about the following corner-case -> When a test is marked as flaky and fails the run (doesn't match the expectation) but passes the run on the retry.

In this case, at the end of the run we currently report as actual results of the tests the union between the first run and the expectations.

So it happens that, for example, when we have a test marked as  "[ Crash Timeout Pass ]" and the fail gives the results "Fail" and "Pass" we currently report the actual results of the tests to be "[ Fail Crash Timeout Pass ]" when "Crash" and "Timeout" didn't happened.

So this makes difficult to know when a tests stops giving a specific result. Once it is marked as flaky with a set of results there is no way to know if some of the results in the set not longer happen.

Here is a test-case to test this:

1. Apply this test patch <http://sprunge.us/MqyGkc> to add a test that fails the 50% of times and passes the other 50% and such test is marked with an expectation of

fast/random/fails-half.html [ Crash Timeout Pass ]

2. Run the test like:

$ Tools/Scripts/run-webkit-tests --no-build --no-show-results --release --results-directory layout-test-results --debug-rwt-logging fast/random/fails-half.html

Repeat the run above until you get the test to fail on the first run and pass on the second.

When that happens you will see this <http://sprunge.us/vwM9B7>:

Unexpected flakiness: text-only failures (1)
  fast/random/fails-half.html [ Crash Timeout Pass Failure ]

And on the json file at layout-test-results/full_results.json you will see:

ADD_RESULTS({"tests":{"fast":{"random":{"fails-half.html":{"report":"FLAKY","expected":"PASS TIMEOUT CRASH","actual":"TEXT PASS TIMEOUT CRASH"}}}}

So I think this is misleading, because the _actual_ result of this test was "FAIL/TEXT" and "PASS" but it didn't give TIMEOUT or CRASH
Comment 1 Carlos Alberto Lopez Perez 2021-10-05 11:42:31 PDT
Created attachment 440241 [details]

Patch fixing the issue. This is the output the above example gives after this patch: http://sprunge.us/ta54tE
Comment 2 Radar WebKit Bug Importer 2021-10-12 11:13:17 PDT
Comment 3 Jonathan Bedard 2021-10-12 11:49:57 PDT
Comment on attachment 440241 [details]

Sorry for the delay looking at this. I was a bit worried about the --repeat case where a test has multiple results. Looks like this performs as expected in that case, though.
Comment 4 EWS 2021-10-14 14:18:52 PDT
Committed r284198 (243012@main): <https://commits.webkit.org/243012@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 440241 [details].