autotest: run Python tests directly from source tree on Windows

[dbaston]

What does this PR do?

Modifies CMake configuration so that Python tests are run directly from the source tree, rather than from a symlink or copy in the build directory. This is an experiment in removing the following "gotcha":

(be careful on Windows, the
content of $build_dir/autotest is copied from $source_dir/autotest each
time "cmake" is run, so if you edit your test .py file directly in the
build directory, be super careful of not accidentally losing your work,
and make sure to copy its content to the source directory first. That's
admittedly an annoying point of the current test setup on Windows,
compared to Unix where we use symbolic links)

described in https://lists.osgeo.org/pipermail/gdal-dev/2024-February/058425.html

A downside of this change is that, because pytest.ini lives only in the build directory, we must always explicitly provide the config file via pytest -c pytest.ini. Is it an overall reduction in complexity? I don't know, am interested in feedback.

What are related issues/pull requests?

Tasklist

• Review
• Adjust for comments
• All CI builds and checks have passed

[coveralls]

coverage: 69.002% (+0.005%) from 68.997%
when pulling fc5fbf3 on dbaston:autotest-no-symlink
into 88b0dd8 on OSGeo:master.

[rouault]

ah, this was mostly me not being aware of the -c option of pytest then. But perhaps we could keep the current symlink approach on non-Windows so that only Windows users have to pay the price of using an inferior operating system ;-) ?

[rouault]

@dbaston do we need to keep that one opened ? I'm trying to reduce the number of staled PRs to keep the list as small as possible.

[dbaston]

I updated this so that the tests are still symlinked on Linux/Mac, so I wasn't planning more work here. It can be merged or closed if we would prefer to continue copying the tests on Windows.

[rouault]

That can be removed. It only made sense on Windows to sometimes speed-up things to avoid repeated copying of the directories. But here we are in the branch that only symlinks.

[rouault]

I updated this so that the tests are still symlinked on Linux/Mac, so I wasn't planning more work here. It can be merged or closed if we would prefer to continue copying the tests on Windows.

ok, sometimes I'm getting lost in what is ready for final review/merge or staled ;-) Don't hesitate to ping me if you see a PR that should be merged

Perhaps https://gdal.org/development/testing.html#running-a-subset-of-tests-using-pytest could get some updates to explain the subtelty on Windows of doing "python -m pytest -c autotest/pytest.ini ../autotest/gcore/vrt_read.py"

[dbaston]

Perhaps https://gdal.org/development/testing.html#running-a-subset-of-tests-using-pytest could get some updates to explain the subtelty on Windows of doing "python -m pytest -c autotest/pytest.ini ../autotest/gcore/vrt_read.py"

Good idea, I've done this at https://github.com/OSGeo/gdal/pull/9224/files#diff-1c899043c9c79440030b3ee7fcf72b357d3333d5070807d933f03ce80b4861edR51