[libgpiod][PATCH v2 0/1] bindings: python: standalone build tooling for tests

[Phil Howard <phil@gadgetoid.com>]

After much delibration about how in-place test builds should work, I have
pulled out all of the test extension code from setup.py into a new
build_tests.py and updated Makefile.am to invoke it.

This replaces the old `python3 setup.py build_ext --inplace` with enough
setuptools tooling to replicate that behaviour, while also putting it
in a better place to avoid problems arising from the deprecation of direct
setup.py invocation [1].

Since receipients of the gpiod Python bindings (in tar.gz source or .whl 
binary format) won't need the test C extensions (and can't run them anyway
without the accompanying Python modules) the test extension code has been
removed from setup.py rather than duplicated into this new file.

The new build_tests.py creates a temporary directory and redirects all
build-time output into it. A final step - handled by build_ext and internal
to setuptools - then moves the built _ext.<python_version>-<arch>-<os>.so C
extensions into gpiod, tests/gpiosim and tests/procname where they can be
imported.

Since release packages and tests no longer share the build/ directory I
have removed the "rmtree" hack from the "build_ext" override in setup.py.
There should be no cases where test extensions can accidentally end up
being installed into the system/user Python environment.

To build and run tests:
- `make python-tests`
- `(sudo) make python-tests-run` (I need root for the gpiosim module)

Tested with setuptools==68.2.2 (Sep 2023), setuptools==59.8.0 (Dec 2021)
and setuptools==42.0.2 (Dec 2019).

Changes v1 -> v2:
- Add the gpiod ext module to build_tests.py (using glob for sources)
- Formalize the command for running tests by adding it to Makefile.am
- Add build_tests.py output artefacts to Makefile.am's clean-local target
- Sort distutils.log imports (DEBUG before set_verbosity)

Phil Howard (1):
  bindings: python: standalone build tooling for tests

 bindings/python/Makefile.am    | 33 +++++++++---
 bindings/python/build_tests.py | 95 ++++++++++++++++++++++++++++++++++
 bindings/python/setup.py       | 28 +---------
 3 files changed, 121 insertions(+), 35 deletions(-)
 create mode 100644 bindings/python/build_tests.py

-- 
2.34.1