React-native-windows: JSI unit tests not running on CI loops.

[JunielKatarn]

Environment

• Visual Studio Version: 2019 (16.3)

• Build Configuration: Debug | x64

Steps to Reproduce

1. Submit any pull request to this repository.

To reproduce locally:

1. yarn install
2. cd vnext
3. nuget restore ReactWindows-Desktop.sln
4. msbuild ReactWindows-Desktop.sln
5. Download https://www.nuget.org/packages/Microsoft.TestPlatform version 16.3.0.
6. Extract the downloaded NUPKG to an arbitrary location.
7. Run <path to extracted NUPKG>\tools\net451\Common7\IDE\Extensions\TestPlatform\vstest.console.exe target\x64\Debug\JSI.Desktop.UnitTests\JSI.Desktop.UnitTests.exe /TestAdapterPath:"C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\Common7\IDE\Extensions\pemwd5jw.szc"

Expected Behavior

Tests for the binary JSI.Desktop.UnitTests.exe are found and run.

Actual Behavior

No tests are discovered:

No test is available in x64\Debug\JSI.Desktop.UnitTests\JSI.Desktop.UnitTests.exe. Make sure that test discoverer & executors are registered and platform & framework version settings are appropriate and try again.

Notes

Because the CI builds currently use a VS2017 VM image, the 16.x test runner must be installed in-place.
An image with an up to date VS2019 could use its own vstest.console.exe that would not trigger this bug.

[NickGerleman]

This should be cheap now that Vlad did the work to get GTest running. @tudorms it could be worth wiring this up with the V8 JSIExecutorFactory once integration goes further

[asklar]

@JunielKatarn I believe we are running VS2019 images in CI now (see vs2019.yml) - so is this still a problem?

[JunielKatarn]

@asklar Not sure. It's specifically about the VSTest framework, not so much about VS.

I'll verify later today.