Add minimal pytest configuration

[gh-tobiasdiez]

Add a minimal pytest configuration, so that calling pytest from src passes without any errors (and without finding any tests for the moment).

This is a preparation for future usages of pytest, such as #30362 or #30738, and is in the general spirit of #28936 (since pytest is perhaps the testing framework for python). For example, one could imagine using pytest doctest_modules to run all sage doctests as well.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​d5c971e

Mark as strict testing, since we pass

[mkoeppe]

This file would need comments at the top that explain its purpose

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​f901922

Add documentation for pytest

[gh-tobiasdiez]

I've now added documentation, also in the tools.rst.

[mkoeppe]

Does this really need the line from __future__ import annotations?

[mkoeppe]

Also, should this not be hooked into tox?

[mkoeppe]

I think it should be said explicitly in the file comments (and the documentation) that this is a no-op and we do not offer ANY tests tested by pytest.

(similar to the wording in the ticket description: "Add a minimal pytest configuration, so that calling pytest from src passes without any errors (and without finding any tests for the moment).")

[gh-tobiasdiez]

Replying to mkoeppe:

Does this really need the line from __future__ import annotations?

Yes, for dict[str, Any].

[gh-tobiasdiez]

Replying to mkoeppe:

Also, should this not be hooked into tox?

That would be the way to go, but I wanted to keep the ticket small (for a change ;-)).

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​bc66a10

Add no-op disclaimer

[gh-tobiasdiez]

Replying to mkoeppe:

I think it should be said explicitly in the file comments (and the documentation) that this is a no-op and we do not offer ANY tests tested by pytest.

Done!

[mkoeppe]

Replying to gh-tobiasdiez:

Replying to mkoeppe:

Also, should this not be hooked into tox?

That would be the way to go, but I wanted to keep the ticket small (for a change ;-)).

I agree. (Given that it's a no-op, there's no point to hook it into tox now.)

[mkoeppe]

Replying to gh-tobiasdiez:

Replying to mkoeppe:

Does this really need the line from __future__ import annotations?

Yes, for dict[str, Any].

Thanks. So it won't be compatible with Python 3.6, but I guess that's OK because we don't really use pytest for anything.

[mkoeppe]

I am getting the following:

$ sage -sh
$ (cd src && pytest)
=========================================================== test session starts ===========================================================
platform darwin -- Python 3.8.6, pytest-6.1.2, py-1.9.0, pluggy-0.13.1
rootdir: /Users/mkoeppe/s/sage/sage-rebasing/worktree-algebraic-2018-spring/src
collected 0 items / 1 error                                                                                                               

================================================================= ERRORS ==================================================================
_____________________________________________ ERROR collecting sage/tests/deprecation_test.py _____________________________________________
ImportError while importing test module '/Users/mkoeppe/s/sage/sage-rebasing/worktree-algebraic-2018-spring/src/sage/tests/deprecation_test.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/usr/local/Cellar/python@3.8/3.8.6/Frameworks/Python.framework/Versions/3.8/lib/python3.8/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
sage/tests/deprecation_test.py:12: in <module>
    from sage.misc.superseded import deprecated_function_alias
sage/misc/superseded.py:30: in <module>
    from sage.misc.lazy_attribute import lazy_attribute
E   ModuleNotFoundError: No module named 'sage.misc.lazy_attribute'
========================================================= short test summary info =========================================================
ERROR sage/tests/deprecation_test.py

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​72ae90f

Clarify that sage has to be installed

[gh-tobiasdiez]

You need to run pytest from a virtual environment where Sage has been installed, since otherwise the imports to cython modules are not resolved (e.g. using the editable install). I've clarified this point in the documentation.

[gh-tobiasdiez]

Does it work for you now?

[mkoeppe]

sage -sh does set up an environment in which python3 is Sage's python (and pytest is from this environment too when it is installed).

[gh-tobiasdiez]

The same code/steps is working for me and correctly reports collected 0 items. I think there is a problem with your setup that cythonized sage modules cannot be found. Can you manually import from sage.misc.lazy_attribute import lazy_attribute?

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​99c4ffd

Merge branch 'develop' of git://github.com/sagemath/sage into public/build/pytest_config

[mkoeppe]

Replying to gh-tobiasdiez:

The same code/steps is working for me

... in your custom setup from #30371, I assume...

and correctly reports collected 0 items. I think there is a problem with your setup that cythonized sage modules cannot be found. Can you manually import from sage.misc.lazy_attribute import lazy_attribute?

Yes.

[gh-tobiasdiez]

Replying to mkoeppe:

Replying to gh-tobiasdiez:

The same code/steps is working for me

... in your custom setup from #30371, I assume...

No, with sage -sh as you did above...

[mkoeppe]

So you have a working standard installation of sage now?

[gh-tobiasdiez]

Yes, after a PC upgrade and with Ubuntu 20.10 in WSL 2 and as many system packages installed it works now. I still prefer my setup from #30371 for testing things though (because of the editable install and the nice integration with vscode).

[gh-tobiasdiez]

I did a bit of googling, and found essentially nothing. The closest was ​https://stackoverflow.com/questions/49068162/pytest-cannot-find-module-on-import-but-code-runs-just-fine/49068163#49068163 but that doesn't suggest a clear solution.

[mkoeppe]

Replying to gh-tobiasdiez:

Yes, after a PC upgrade and with Ubuntu 20.10 in WSL 2 and as many system packages installed it works now. I still prefer my setup from #30371 for testing things though (because of the editable install and the nice integration with vscode).

Great. So how about reducing #30371 then, finally, to something that makes the editable install work on top of the normal installation via the distribution?

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​bf014ba

Enforce that test files need to end on _test.py

[mkoeppe]

As discussed in #31103, src/bin/sage-coverage, src/bin/sage-coverageall will need updating so that they do not complain about ..._test.py files. (They are also used by the patchbot.)

[mkoeppe]

Developer's guide (src/doc/en/developer/) would need updates in

• coding_basics.rst
• reviewer_checklist.rst

[gh-tobiasdiez]

Can I do this as follow-up tickets? The purpose of this one here was to provide a minimal test configuration that works for sage. Using pytest in an effective way definitely needs more changes in various areas.

[mkoeppe]

Replying to gh-tobiasdiez:

Can I do this as follow-up tickets?

Sure

[gh-tobiasdiez]

Ok, this is now #31123.

Can you please retry if it works for you? For me sage -sh followed by pip install pytest and pytest works. You need to run pytest from a python installation in which sage is installed including the Cython modules.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​38e210e

Merge branch 'develop' of git://github.com/sagemath/sage into public/build/pytest_config

[gh-tobiasdiez]

Still needs review.

[mkoeppe]

The issue persists. I think the problem is that, when executing pytest from the src directory, the subdirectory sage (which does not have the compiled modules) shadows the installed sage package. So I think you need to set some option for pytest so that . is not in the path.

[gh-tobiasdiez]

I read a bit more about it, and in order for pytest to find cython modules you need to use an editable install (that's why it was always working for me, regardless of how I started pytest). For now, I've added deprecation_test.py to the ignored list, so the issue should be fixed.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​62b1c61

Igonre deprecation_test as well

[mkoeppe]

OK this looks like a nice clean no-op now.

[gh-tobiasdiez]

Thanks!

[vbraun]

Documentation doesn't build

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​462f071

Fix documentation

[gh-tobiasdiez]

Sorry overlooked this. Since the fix was trivial, I'll put it back to "positive review".