System.IO.Tests.File_Move_Tests.File_Move_Multiple_From_Watched_To_Unwatched_Mac test failure

[jkotas]

  Discovered:  System.IO.FileSystem.Watcher.Tests (found 166 of 210 test cases)
  Starting:    System.IO.FileSystem.Watcher.Tests (parallel test collections = on [6 threads], stop on fail = off)
    System.IO.Tests.File_Move_Tests.File_Move_Multiple_From_Watched_To_Unwatched_Mac(filesCount: 2) [FAIL]
      Assert.Equal() Failure: Collections differ
                                                                                                                                                                              ↓ (pos 1)
      Expected: ArraySelectIterator<<>f__AnonymousType1<string, string>, FiredEvent> [Deleted /tmp/helix/working/9FEF0885/t/#File_Move_Tests_r5rmsjek.mw5/dir_watched/file0 , Deleted /tmp/helix/working/9FEF0885/t/#File_Move_Tests_r5rmsjek.mw5/dir_watched/file1 ]
      Actual:   List<FiredEvent>                                                     [Deleted /tmp/helix/working/9FEF0885/t/#File_Move_Tests_r5rmsjek.mw5/dir_watched/file0 , Deleted /tmp/helix/working/9FEF0885/t/#File_Move_Tests_r5rmsjek.mw5/dir_watched/file0 , Deleted /tmp/helix/working/9FEF0885/t/#File_Move_Tests_r5rmsjek.mw5/dir_watched/file1 ]
                                                                                                                                                                              ↑ (pos 1)
      Stack Trace:
        /_/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.File.Move.cs(234,0): at System.IO.Tests.File_Move_Tests.FileMove_Multiple_FromWatchedToUnwatched(Int32 filesCount, Boolean skipOldEvents)
        /_/src/libraries/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.File.Move.cs(48,0): at System.IO.Tests.File_Move_Tests.File_Move_Multiple_From_Watched_To_Unwatched_Mac(Int32 filesCount)
           at System.Object.InvokeStub_File_Move_Tests.File_Move_Multiple_From_Watched_To_Unwatched_Mac(Object, Span`1)
        /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs(95,0): at System.Reflection.MethodBaseInvoker.InvokeWithOneArg(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
    System.IO.Tests.FileSystemWatcherTests_netstandard17.DroppedWatcher_Collectible [SKIP]
      Condition(s) not met: "IsPreciseGcSupported"
  Finished:    System.IO.FileSystem.Watcher.Tests

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1314668
Build error leg or test failing: System.IO.Tests.File_Move_Tests.File_Move_Multiple_From_Watched_To_Unwatched_Mac
Pull request: #125014

Error Message

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

{
  "ErrorMessage": "",
  "ErrorPattern": "System.IO.Tests.File_Move_Tests.File_Move_Multiple_From_Watched_To_Unwatched_Mac.*FAIL",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1314668
Error message validated: [System.IO.Tests.File_Move_Tests.File_Move_Multiple_From_Watched_To_Unwatched_Mac.*FAIL]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 3/1/2026 12:32:32 AM UTC

Report

Build	Definition	Test	Pull Request
1314668	dotnet/runtime	System.IO.Tests.File_Move_Tests.File_Move_Multiple_From_Watched_To_Unwatched_Mac	#125014
1313887	dotnet/runtime	System.IO.Tests.File_Move_Tests.File_Move_Multiple_From_Watched_To_Unwatched_Mac	#124989

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	2	2

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[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• FileSystemWatcher tests on MacOS constantly fail on Outerloop CI run #31383