Proper CI test runner for Linux and MacOS

[HendrikHuebner]

The CI currenly does not actually run any tests and just attempts to compile everything on Linux. I propose the following improvements:

1. Actually run the tests on every pr-push (duh)

• currently we're only doing ./configure ...; make; make install
• instead, run the full test suite, report failures, number of "dashed hopes" and code coverage

2. Validate test suite against Apple's CoreFoundation

• Add a workflow which runs in a macos container (Triggered manually)
• A script discovers all the tests. Test files can be marked to skip them.
• Compile and run each test against Apple Foundation/CoreFoundation.

I ran the tests myself in a Linux docker container and noticed a couple of failures. Some of them are fixed by @DTW-Thalion's PRs, others will still need adressing. Most tests compile for MacOS (Some needed minor fixes, like missing headers). Many fail (especially things related to string parsing / formatting), but we can make most work without too much effort and guard problematic assertion with #if defined(__APPLE__).

For now I would recommend accepting more of the bug fixes, such as #57. I'll submit a set of scripts / improved workflows and workarounds to make the CI green. Once that is in place, we can continue adding tests with confidence, that we are actually testing the right behavior.

[HendrikHuebner]

cc @stefanbidi @triplef

[DTW-Thalion]

Agree on both parts.

For (1), the Linux side is a small addition to compile.yaml: the suite already wires up to gnustep-tests through Tests/GNUmakefile, so it's mostly a make check step after the existing install, surfacing the pass/fail/dashed-hopes counts from Tests/tests.sum.

On "accept more bug fixes to make CI green" — the highest-leverage ones are the fixes for tests that abort the whole file, since a single abort halts that file and hides everything after it. From the failure logs those are:

• CFTree/basic.m aborted → CFTree: fix null-pointer dereferences in child handling #49, CFTree: fix CFTreeRemove so it actually unlinks the node #50, CFTree: retain children and the context info #51
• CFAttributedString/mutable.m aborted → CFAttributedString: fix allocation, use-after-free and OOB bugs #53
• CFTimeZone/general.m aborted → CFTimeZone: retain timezones stored in the name cache (use-after-free) #67 (with CFTimeZone: lock the timezone-cache lookup (data race) #64, CFTimeZone: validate TZif header counts before parsing #41)

Merging those should turn several "Failed file: aborted" lines into clean runs. #57 is another good one, as you noted.

For (2), agreed the remaining Linux/macOS differences are mostly ICU/locale and number/date formatting. I'm happy to help guard those with #if defined(__APPLE__) / skip markers, and to keep new test PRs documentation-based and free of CoreBase internals per @stefanbidi's guidance. Since you're already assembling the workflow I'll hold off on that and focus on the tests + guarding — just say how you'd like to coordinate.