Couldn't shim OperatingSystem.IsWindows()

[kohanyirobert]

I'm trying to shim OperatingSystem.IsWindows() but bump into an error. Shimmed call seem to return null.

I created a minimal working example, here: https://github.com/kohanyirobert/pose-os-shim/

This uses .NET 8, same happens in .NET 9 tho'.

Is this even possible? The underlying method uses conditional compilation (using #if WINDOWS or such), not sure if this is an issue or not.

> dotnet test
Restore complete (0,2s)
  pose-os-shim succeeded (0,4s) → bin\Debug\net8.0\pose-os-shim.dll
[xUnit.net 00:00:00.00] xUnit.net VSTest Adapter v3.0.2+dd36e86129 (64-bit .NET 8.0.13)
[xUnit.net 00:00:00.21]   Discovering: pose-os-shim
[xUnit.net 00:00:00.35]   Discovered:  pose-os-shim
[xUnit.net 00:00:00.51]   Starting:    pose-os-shim
[xUnit.net 00:00:00.58]     poser_os_shim.UnitTest1.Test1 [FAIL]
[xUnit.net 00:00:00.58]       Assert.False() Failure
[xUnit.net 00:00:00.58]       Expected: False
[xUnit.net 00:00:00.58]       Actual:   null
[xUnit.net 00:00:00.58]       Stack Trace:
[xUnit.net 00:00:00.58]            at impl_Xunit.Assert_False(Nullable`1, String)
[xUnit.net 00:00:00.58]            at impl_poser_os_shim.UnitTest1+<>c_<Test1>b__0_2(<>c)
[xUnit.net 00:00:00.58]            at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
[xUnit.net 00:00:00.58]            at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
[xUnit.net 00:00:00.59]   Finished:    pose-os-shim
  pose-os-shim test failed with 1 error(s) (1,3s)
    C:\Users\rkohanyi\Work\pose-os-shim\bin\Debug\net8.0\pose-os-shim.dll : error TESTERROR:
      poser_os_shim.UnitTest1.Test1 (41ms): Error Message: Assert.False() Failure
      Expected: False
      Actual:   null
      Stack Trace:
         at impl_Xunit.Assert_False(Nullable`1, String)
         at impl_poser_os_shim.UnitTest1+<>c_<Test1>b__0_2(<>c)
         at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
         at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)

Test summary: total: 1; failed: 1; succeeded: 0; skipped: 0; duration: 1,3s
Build failed with 1 error(s) in 2,4s