tests: enable test_importlib subpackage (#491)

[ada-x64]

Summary

Changes

Enables the full test_importlib sub-package (45 test files across 9 sub-areas: source, frozen, extension, resources, import_, builtin, namespace_pkgs, partial, data) on Nanvix. Adds test_importlib to NANVIX_TEST_LIST with @unittest.skipIf annotations for the failure classes that surface on FAT VFS, linuxd, and the static-link build.

Verified GREEN on both modes:

Mode	Result
standalone	91/91 modules / 23/23 batches PASS
single-process	94/94 modules / 24/24 batches PASS

Also: .nanvix/run-tests.py direct (hosted) branch now passes -B, symmetric with the standalone branch which already does so. Without -B, importing any source whose mtime is newer than its compiled pyc hangs the guest kernel via NSKIP055 (linuxd os.replace hang); this is mandatory infrastructure for hosted, not a test-specific workaround.

New NSKIPS

NSKIP code	Description
NSKIP054	Nanvix is built static-only; no dynamic extension modules (.so) available
NSKIP055	linuxd rename()/replace() hangs the kernel on hosted Nanvix

NSKIP055 is the hosted analog of NSKIP021: same user-visible symptom (os.rename/os.replace hangs the kernel), but a distinct bug in a different VFS layer (linuxd RPC vs rust-fatfs). Independently fixable, so it gets its own ID. Every test that exercises rename now stacks both decorators (NSKIP021 fires on standalone, NSKIP055 on hosted).

NSKIP054 covers the static-link build: importlib.machinery.EXTENSION_SUFFIXES is non-empty but no .so file exists on sys.path, so util.EXTENSIONS.filename stays None and the upstream Requires dynamic loading support. skip guard does not fire. Affects every test in extension/test_loader.py and extension/test_finder.py.

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Refs: NSKIP008, NSKIP012, NSKIP016, NSKIP021, NSKIP026, NSKIP043, #371, #490
Closes #491.

[Copilot]

Pull request overview

Enables CPython’s test_importlib subpackage in the Nanvix test suite by adding it to the Nanvix test list and applying Nanvix-specific skips for known kernel/VFS limitations (standalone FAT VFS, hosted linuxd passthrough, and static-only builds). It also adjusts the Nanvix test harness to avoid hosted hangs by running the guest Python with -B in direct mode.

Changes:

• Add test_importlib to the Nanvix test module allowlist and enable running its sub-areas with targeted NSKIP-based skips.
• Introduce/extend Nanvix platform discrimination in test support and update multiple tests to skip known-failing/hanging cases.
• Update .nanvix/run-tests.py direct-mode invocation to pass -B to prevent hosted kernel hangs during bytecode writes.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.github/workflows/nanvix-ci.yml	CI workflow adjustments related to updated Nanvix testing.
.nanvix/build.py	Build tooling tweaks supporting updated test enablement.
.nanvix/config.py	Adds test_importlib to NANVIX_TEST_LIST.
.nanvix/nanvix.toml	Pins/updates Nanvix tooling configuration.
.nanvix/package.py	Packaging/tooling updates for the new test surface.
.nanvix/run-regrtest.py	Removes/adjusts regrtest runner logic for new harness behavior.
.nanvix/run-tests.py	Passes -B in direct mode; documents hosted rename/replace hang.
.nanvix/test.py	Expands test orchestration/filters to include test_importlib.
.nanvix/z.py	Refactors/updates Nanvix zutil script behaviors for new flows.
Lib/test/support/init.py	Adds Nanvix topology helpers and hosted cleanup workarounds.
Lib/test/support/os_helper.py	Nanvix-specific filesystem/test cleanup accommodations.
Lib/test/support/socket_helper.py	Updates socket helper behavior for Nanvix constraints.
Lib/test/test_array.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_ast.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_builtin.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_code.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_collections.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_contextlib.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_coroutines.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_decimal.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_defaultdict.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_deque.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_dict.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_exception_group.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_exceptions.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_fractions.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_functools.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_importlib/extension/test_finder.py	Skips extension-module tests on static-only Nanvix.
Lib/test/test_importlib/extension/test_loader.py	Skips extension-module tests on static-only Nanvix.
Lib/test/test_importlib/import_/test_path.py	Adds Nanvix skips for known cleanup failures.
Lib/test/test_importlib/resources/test_path.py	Skips hosted Nanvix due to rmtree/rmdir cleanup issues.
Lib/test/test_importlib/resources/test_resource.py	Adds hosted Nanvix skips for cleanup-related failures.
Lib/test/test_importlib/source/test_case_sensitivity.py	Skips standalone Nanvix for FAT case/8.3 behavior.
Lib/test/test_importlib/source/test_file_loader.py	Skips Nanvix modes affected by rename/replace hangs.
Lib/test/test_importlib/source/test_finder.py	Skips Nanvix modes affected by rename/replace hangs.
Lib/test/test_importlib/source/test_source_encoding.py	Skips standalone Nanvix due to rename hang surface.
Lib/test/test_importlib/test_api.py	Adds Nanvix skips around reload/rename behaviors.
Lib/test/test_importlib/test_lazy.py	Skips threaded race test on Nanvix thread-limit constraints.
Lib/test/test_importlib/test_locks.py	Skips module on Nanvix due to thread-limit constraints.
Lib/test/test_importlib/test_main.py	Adds hosted Nanvix skips for cleanup failures; targeted skips.
Lib/test/test_importlib/test_metadata_api.py	Adds hosted/standalone Nanvix skips for known VFS errnos.
Lib/test/test_importlib/test_namespace_pkgs.py	Adds hosted Nanvix skip for cleanup failures.
Lib/test/test_importlib/test_pkg_import.py	Adds hosted/rename-hang related skips for Nanvix.
Lib/test/test_importlib/test_threaded_import.py	Skips module on Nanvix due to thread-limit constraints.
Lib/test/test_importlib/test_util.py	Adds Nanvix skips for rename/replace hang cases.
Lib/test/test_int.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_iter.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_itertools.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_list.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_math.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_operator.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_ordered_dict.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_queue.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_random.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_range.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_reprlib.py	Adds/updates Nanvix skip coverage for cleanup limitations.
Lib/test/test_set.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_slice.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_statistics.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_super.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_tuple.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_types.py	Adds Nanvix skips/adjustments for newly enabled coverage.
Lib/test/test_weakref.py	Adds Nanvix skips/adjustments for newly enabled coverage.
z.ps1	Syncs bootstrap script with updated zutils template/version.
z.sh	Syncs bootstrap script with updated zutils template/version.

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