[meta] Known intermittent, random, and environment-specific test failures

This issue is intended as a tracking issue only to list all of the known intermittent test failures affecting Drupal core. Some issues are due to bugs in Drupal core; others may be due to issues with DrupalCI infrastructure.

Only open issues should be listed in the summary.

Consistent failures

• #2921123: Adjust Rectangle class to calculate rotated image dimensions according to libgd 2.2.2+

Intermittent failures

1. #2825845: DST-related test failures in FilterDateTimeTest
2. #2920590: (canard?) Big Bos of Random Fails is ChainedFastBackend::markAsOutdated()
3. #3041318: Various random fails due to mis-triggered Mink deprecation error
4. #3143812: [random test failure] Table 'sequences' already exists.
5. #3150040: [random test failure] ScaffoldUpgradeTest and ScaffoldTest rely on packagist.org
6. #3203712: [random test failure] EntityDisplayTest::testExtraFields()
7. #3203712: [random test failure] EntityDisplayTest::testExtraFields()
8. #3273626: Resolve issue with tests for Drupal Media JavaScript causing database locks on SQLite
9. #3317520: [random test failure] Drupal\Tests\settings_tray\FunctionalJavascript\SettingsTrayBlockFormTest::testEditModeEnableDisable
10. #3354138: [random test failure] MenuUiTest::testMenuAdministration can generate "escaped locator"
11. #3387939: [random test failure] ToolbarClaroOverridesTest fails intermittently
12. #3389994: [random test failure] MediaTest::testViewMode
13. #3390881: [random test failure] Drupal.Tests.media_library.FunctionalJavascript.FieldUiIntegrationTest
14. #3393137: [random test failure] SettingSummariesContentTypeTest::testWorkflowSummary
15. #3393477: [random test failure] LocaleUpdateTest
16. #3397387: [random test failure] MediaLinkabilityTest sometimes fails
17. #3400150: [random test failure] TimestampFormatterWithTimeDiffTest::testTimestampFormatterWithTimeDiff
18. #3406418: [gitlab-runner] invalid limit quantity for empty volume
19. #3414321: [random test failure] Fail in mysql\ConnectionUnitTest::testOpenQueryPrefetchClose
20. #3420399: [META] Random failures in Functional JavaScript Performance test(s)
21. #3468830: [random test failure] BlockCacheTest::testCachePermissions()
22. #3477586: [random test failure] LayoutBuilderBlocksTest::testBlockPlaceholder failing

Low fail rate or may be resolved

• #3057767: [random test failure] DialogTest::testDialog() (failed 13 Mar 2023 for 10.0.x-dev test with PHP 8.1 & pgsql-14.1

Investigation and hardening for past random failures

• #2936432: Review use of pressButton() in functional javascript tests in the Media module
• #2946294: Fix race conditions in OffCanvasTestBase
• #2856047: Avoid random failures in JavascriptTestBase when testing functionality in a dialog
• #3055983: Occasional locks on SQLite
• #2571183: Deprecate random() usage in tests to avoid random test failures
• #3165263: Allow known flaky tests to be automatically repeated

If your patch has an unexpected test failure

1. Always click on the test results link to see what tests actually failed.
2. Check the test results on https://www.drupal.org/node/3060/qa. If the same test appears to be failing on the "tested on commit" environments, HEAD may be broken.
3. Most test failures are actually caused by bugs in patches. Even if a failure appears to be random, consider that the patch may be introducing the bug.
4. If the test result says "CI error" or "CI aborted", that generally indicates an issue with the infrastructure and not with the patch. Wait a bit, then requeue the tests for the patch.
5. If the test says "Fatal error" with no other information, click "View results on dispatcher", then "Console Output", then "Full log", and search on the page for "segmentation fault". #2859704: Intermittent segfaults on DrupalCI (some "did not complete due to a fatal error" with no additional info) is a known issue that may cause the test runner to report a fatal in different tests.
6. If the test failure appears to be one of the above known failures, there is no need to add additional reports of it (unless the issue specifically requests so). Usually, once a fail is identified, Drupal.org maintainers can locate other, similar fails in server logs if needed. However, you should document on your issue which specific known issue caused the failure.
7. If there is an unexpected test failure that is not covered by one of the above issues, file a new critical issue and add it to this issue's summary.