Run tests in CI

[nettle]

Why: we have GitHub action but it does not run any tests

What:

• Set Clang version (append particular llvm version to PATH)
• Check tools (which and versions)
• Run Bazel test
• Run unit tests
• Remove --stats (not supported by open-source CodeChecker)
• Change extension to yaml

[Szelethus]

I'm personally strongly in favour of letting the original author finish the original work and learn in the process. It's fine to submit totally alterantive solutions to the same problem, we gained a lot from doing that in #21, but not quite the same solution with marginal differences.

GITHUB_PATH is interesting, but doesn't align with the, unfortunately only spoken, agreed on goals. The goal as I understand was to keep everything as simple as possible, representative of how a new user/contributor would set up their environment, which this GitHub Workflow specific solution doesn't achieve.

I think this should've been discussed as an idea in #28 and it is what I'd encourage moving forward.

[nettle]

I'm personally strongly in favour of letting the original author finish the original work and learn in the process.

That's totally fine with me. I'm not insisting on anything, just showing alternative approaches.

GITHUB_PATH is interesting, but doesn't align with the, unfortunately only spoken, agreed on goals. The goal as I understand was to keep everything as simple as possible, representative of how a new user/contributor would set up their environment, which this GitHub Workflow specific solution doesn't achieve.

Well, as I understand GITHUB_PATH is a standard GitHub Action approach (Adding a system path), which is equivalent to export PATH=/usr/lib/llvm-18/bin:$PATH. So, to me personally it looks a way simpler and much more flexible. But again, I'm not insisting.

I think this should've been discussed as an idea in #28 and it is what I'd encourage moving forward.

Also fine with me.

[Szelethus]

Landed in #28.