Build `tests.*` listed as changed paths

[ShamrockLee]

OfBorg currently build packages whose expression is changed directly by the PR, but not the affected downstream packages. But we could consider building changed derivations under tests.* even if their expressions are not changed directly, as they are meant to be tested.

I'm not sure if we would like to avoid running NixOS tests (as they would be expensive) inside OfBorg. If so, it would be better to get a way to detect if a test derivation is a NixOS tests, instead of opting out everything under tests.

Update: test cases under pkgs.tests are all package tests.

[Artturin]

pkgs.tests doesn't contain nixos tests nor is it meant to.

EDIT:
You meant passthru.tests? There's no way to indirectly get what's changed in passthru without recursing everything.

[ShamrockLee]

pkgs.tests doesn't contain nixos tests nor is it meant to.

Thank you for explaining. I confused the term "NixOS tests" with package tests implemented with runNixOSTest (e.g. tests.trivial-builders.references).