Make running django's test suite easier

[Anssi Kääriäinen]

Two suggested changes to tests/runtests.py:

1. Automatically use tests/../django as the Django version.
2. If no other settings given (either through --settings or DJANGO_SETTINGS_MODULE) then use test_sqlite as settings

Both of the above changes are available from: ​https://github.com/akaariai/django/compare/test_auto_settings

The first item raises a question: is there some use case where one wants to run tests against *different* django version? To me it seems one wouldn't want to do this, the tests are tied to specific django version.

I can't see any drawback by doing the second item.

[Florian Apolloner]

I fully agree with 1. and 2. -- I am against supporting other Django versions.

[Aymeric Augustin]

LGTM, with the caveat that the long term goal is to get rid of runtests.py, not extend it...

[Aymeric Augustin]

Not RFC yet in fact :)

[Tim Graham]

​PR with update docs.

[loic84]

Looks good to me.

[Tim Graham]

I'm unsure why import django is needed? Also the comment in the docstring of upath references a "try-except of import django" which isn't present.

[loic84]

I spotted the import django and I assumed it was meant as an assert.

In light of the docstring, maybe the idea was to provide a helpful error message?

[Tim Graham <timograham@…>]

In b2314d9e1e08749f2c05151f9cd44520d2b3a03a:

Fixed #19941 -- Modified runtests.py to make running the tests easier.

1. Automatically use tests/../django as the Django version.
2. If settings aren't provided through --settings or DJANGO_SETTINGS_MODULE) then use test_sqlite.

[Jannis Leidel]

Reopening the sys.path.insert call makes the test setup differ from standard installation procedures. We've for a long time tried hard to move away from modifying the sys.path.

As a background, by mangling the sys.path we risk missing import errors that happen when Django is installed with tools like pip. Instead we should promote the use of pip install -e path/to/django when developing Django.

[Florian Apolloner]

After discussing this a bit more with jezdez in IRC we came to the following conclusion:

• pip install -e . isn't perfect (in the sense that it doesn't mimic a sdist install by 100%) but still better than sys.path hacks.
• drop sys.path hacks again.
• Update the documentation to note pip install -e and PYTHONPATH=.. alternatives.
• Output something like print("Testing against Django installed in '%s'" % django.__file__) to the console, to allow easier debugging.

[Tim Graham]

​Pull request with changes proposed above.

[Tim Graham <timograham@…>]

In c573d6de173c0e6743473081cde786e749641a48:

Fixed #19941 -- Removed sys.path hack when running the test suite.

Thanks jezdez for the suggestion.