Re: [PATCH v2 11/15] iotests: split linters.py out from 297

[Hanna Reitz]

On 26.10.21 20:30, John Snow wrote:
> On Tue, Oct 26, 2021 at 6:51 AM Hanna Reitz <hreitz@redhat.com> wrote:
>
>     On 19.10.21 16:49, John Snow wrote:
>     > Now, 297 is just the iotests-specific incantations and
>     linters.py is as
>     > minimal as I can think to make it. The only remaining element in
>     here
>     > that ought to be configuration and not code is the list of skip
>     files,
>     > but they're still numerous enough that repeating them for mypy and
>     > pylint configurations both would be ... a hassle.
>     >
>     > Signed-off-by: John Snow <jsnow@redhat.com>
>     > ---
>     >   tests/qemu-iotests/297        | 72
>     +++++----------------------------
>     >   tests/qemu-iotests/linters.py | 76
>     +++++++++++++++++++++++++++++++++++
>     >   2 files changed, 87 insertions(+), 61 deletions(-)
>     >   create mode 100644 tests/qemu-iotests/linters.py
>
>     Reviewed-by: Hanna Reitz <hreitz@redhat.com>
>
>
> Thanks!
>
>     I wonder about `check_linter()`, though.  By not moving it to
>     linters.py, we can’t use it in its entry point, and so the Python
>     test
>     infrastructure will have a strong dependency on these linters. Though
>     then again, it probably already does, and I suppose that’s one of the
>     points hindering us from running this from make check?
>
>
> That one is left behind because it uses iotests API to skip a test. 
> Environment setup that guarantees we won't *need* to skip the test is 
> handled by the virtual environment setup magic in qemu/python/Makefile.
>
>     Hanna
>
>
> More info than you require:
>
> There's maybe about four ways you could run the python tests that 
> might make sense depending on who you are and what you're trying to 
> accomplish; they're documented in "make help" and again in 
> qemu/python/README.rst;
>
> (1) make check-dev -- makes a venv with whatever python you happen to 
> have, installs the latest packages, runs the tests
> (2) make check-pipenv -- requires python 3.6 specifically, installs 
> the *oldest* packages, runs the tests
> (3) make check-tox -- requires python 3.6 through 3.10, installs the 
> newest packages, runs the tests per each python version
> (4) make check -- perform no setup at all, just run the tests in the 
> current environment. (Used directly by all three prior invocations)

AFAIU these are all to be run in build/python?  Isn’t any of them hooked 
up to the global `make check` in build?  Because...

> In general, I assume that human beings that aren't working on Python 
> stuff actively will be using (1) at their interactive console, if they 
> decide to run any of these at all.

...I’m just running `make check` in the build directory.

I would have hoped that this is hooked up to something that won’t fail 
because I don’t have some necessary tools installed or perhaps even 
because I have the wrong version of some tools installed (although the 
latter would be kind of questionable...).  Would be nice if the global 
`make check` had a summary on what was skipped...

> It imposes the least pre-requirements while still endeavoring to be a 
> target that will "just work".
> Options (2) and (3) are what power the CI tests 'check-python-pipenv' 
> and 'check-python-tox', respectively; with(2) being the one that 
> actually gates the CI.
> Option (4) is only really a convenience for bypassing the venv-setup 
> stuff if you want to construct your own (or not use one at all). So 
> the tests just assume that the tools they have available will work. 
> It's kind of a 'power user' target.
>
> The way the CI works at the moment is that it uses a "fedora:latest" 
> base image and installs python interpreters 3.6 through 3.10 
> inclusive, pipenv, and tox. From there, it has enough juice to run the 
> makefile targets which take care of all of the actual linting 
> dependencies and their different versions to get a wider matrix on the 
> version testing to ensure we're still keeping compatibility with the 
> 3.6 platform while also checking for new problems that show up on the 
> bleeding edge.

Perhaps it’s unreasonable, but I’d prefer if a local `make check` would 
already run most tests in some form or another and that I don’t have to 
push to gitlab and wait for the CI there.

I mean, I can of course also integrate a `cd python && make check-dev` 
invocation into my test scripts, but it doesn’t feel right to 
special-case one test area.

> iotests 297 right now doesn't do any python environment setup at all, 
> so we can't guarantee that the linters are present, so we decide to 
> allow the test to be skipped. My big hesitation of adding this test 
> directly into 'make check' is that I will need to do some environment 
> probing to make sure that the 'pylint' version isn't too old -- or 
> otherwise set up a venv in the build directory that can be used to run 
> tests. I know we already set one up for the acceptance tests, so maybe 
> there's an opportunity to re-use that venv, but I need to make sure 
> that the dependencies between the two sets of tests are aligned. I 
> don't know if they agree, currently.

I see.

> I think I probably want to minimize the number of different virtual 
> python environments we create during the build, so I will look into 
> what problems might exist in re-purposing the acceptance test venv. If 
> that can get squared away easily, there's likely no real big barrier 
> to adding more tests that rely on a python venv to get cooking during 
> the normal build/check process, including iotest 297.

OK, thanks for the explanation!

Hanna