Description

We previously had a separate set of unit tests for each platform; now that we're adding platforms (3 already, a 4th about to be added for ARM) it's starting to become unwieldy. Instead, this PR combines all the unit tests into a single directory, (attempting to) run every unit test on every platform. The Windows-only tests will run on Linux too, generating the corresponding error message (thus obviating the need for the previous invalid tests to make sure they don't work on Linux), etc.

To preserve the existing behavior of making sure that invalid tests always fail, if the test name begins with invalid- the code will expect that the test should fail on every platform.

Related issue

b/274913389 and b/283086085

How has this been tested?

Unit tests continue to pass. I carefully moved the existing golden files into place and verified the diffs by hand before using go test . -update to generate the missing golden files.

Checklist:

• Unit tests
  • Unit tests do not apply.
  • Unit tests have been added/modified and passed for this PR.
• Integration tests
  • Integration tests do not apply.
  • Integration tests have been added/modified and passed for this PR.
• Documentation
  • This PR introduces no user visible changes.
  • This PR introduces user visible changes and the corresponding documentation change has been made.
• Minor version bump
  • This PR introduces no new features.
  • This PR introduces new features, and there is a separate PR to bump the minor version since the last release already.
  • This PR bumps the version.