TimeZoneInfoTests.NoBackwardTimeZones tests are failing on Android

[tarekgh]

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1096605 Build error leg or test failing: System.Tests.TimeZoneInfoTests.NoBackwardTimeZones Pull request: https://github.com/dotnet/runtime/pull/117630

07-16 11:57:57.303 28828 28920 I DOTNET  : 1) 	[FAIL] System.Tests.TimeZoneInfoTests.NoBackwardTimeZones   Test name: System.Tests.TimeZoneInfoTests.NoBackwardTimeZones
07-16 11:57:57.303 28828 28920 I DOTNET  :    Assembly:  [System.Runtime.Tests, Version=10.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51]
07-16 11:57:57.303 28828 28920 I DOTNET  :    Exception messages: Assert.Equal() Failure: Values differ
07-16 11:57:57.303 28828 28920 I DOTNET  : Expected: 596
07-16 11:57:57.303 28828 28920 I DOTNET  : Actual:   450   Exception stack traces:    at System.Tests.TimeZoneInfoTests.NoBackwardTimeZones()
07-16 11:57:57.303 28828 28920 I DOTNET  :    at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
07-16 11:57:57.303 28828 28920 I DOTNET  :    at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": "Exception stack traces:    at System.Tests.TimeZoneInfoTests.NoBackwardTimeZones()",
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: :mag_right: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1096605 Error message validated: [Exception stack traces: at System.Tests.TimeZoneInfoTests.NoBackwardTimeZones()] Result validation: :white_check_mark: Known issue matched with the provided build. Validation performed at: 7/16/2025 7:00:02 PM UTC

Report

Build	Definition	Test	Pull Request
1096605	dotnet/runtime	System.Runtime.Tests.WorkItemExecution	dotnet/runtime#117630

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
1	1	1

Report

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	0	0

[dotnet-policy-service[bot]]

Tagging subscribers to 'arch-android': @vitek-karas, @simonrozsival, @steveisok, @akoeplinger See info in area-owners.md if you want to be subscribed.

[dotnet-policy-service[bot]]

Tagging subscribers to this area: @dotnet/area-system-datetime See info in area-owners.md if you want to be subscribed.

[steveisok]

@matouskozak if this flakes, it might be something weird with a specific device or devices.

[tarekgh]

This looks that OS's are getting new TZ data. Look at https://github.com/dotnet/runtime/issues/117422 which is reported on macOS 26 Preview 3.

[matouskozak]

@matouskozak if this flakes, it might be something weird with a specific device or devices.

Indeed, I looked into the history, and it is only failing on DNCENGWIN-140 device since 2025-07-10 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1091157&view=results (only on PRs).