[py-dev] new resource API documentation comments

[Brianna Laugher]

Also,

Would this be a roughly equivalent old-style to the smtp examples in
http://pytest.org/dev/funcargs.html ?


def pytest_funcarg__smtpMerLinux(request):
    smtp = smtplib.SMTP("merlinux.eu")
    def teardown(smtp):
        print ("finalizing %s" % smtp)
        smtp.close()
    return request.cached_setup(setup=lambda: smtp, teardown=teardown,
scope='session')


def pytest_funcarg__smtpMailPython(request):
    smtp = smtplib.SMTP("mail.python.org")
    def teardown(smtp):
        print ("finalizing %s" % smtp)
        smtp.close()
    return request.cached_setup(setup=lambda: smtp, teardown=teardown,
scope='session')

# test file
def pytest_generate_tests(metafunc):
    merlinux = request.getfuncargvalue('smtpMerLinux')
    mailpython = request.getfuncargvalue('smtpMailPython')

    if'smtp' in metafunc.funcargnames:
        metafunc.addcall(id='merlinux.eu', param=merlinux) # ? would
this work? seems magic
        metafunc.addcall(id='mail.python.org', param=mailpython)

I feel like this makes it clear how much more powerful parametrizing
funcargs themselves is.

cheers
Brianna




On 16 August 2012 18:58, Brianna Laugher <brianna.laugher at gmail.com> wrote:
> Hi,
>
> I just spent some time reading the dev docs so these comments are just
> based on the docs and not actually using the new API. In general it
> looks pretty sensible.
>
> - being able to have funcargs like funcargs directly is really nice, a
> lot more obvious than calling request.getfuncargvalue('foo')
> - why addfinalizer and not teardown?
> -although I don't really know what cached_setup did, the trinity of
> defining the scope, setup and teardown methods made sense to me. Now
> the scope is in a decorator, the setup is implicitly the entire thing
> that is happening and the teardown seems somewhat awkwardly tacked on.
> - none of the "addfinalizer" examples take an argument, how would you
> convert an old-style teardown method to that? e.g. we have a lot of
> funcargs which do things like
>     return request.cached_setup(setup=setup,
>                                 teardown=lambda obj: obj.close(),
>                                 scope='function')
> - Sometimes things are referred to as "funcargs", sometimes they are
> referred to as "injected resources". Is there any difference here? The
> funcarg is the actual function and the injected resource is the
> instance in a specific test function? I suggest to use the term
> "funcarg" as much as possible as it is specific and a necessary
> concept for using pytest with any depth.
>
> Some of the following comments are fairly picky so feel free to ignore them.
>
> funcargs.txt
> line 118 - I think in this first incarnation of the smtp funcarg
> (factory? what to call it now?), it doesn't actually need to take a
> testcontext, right?
>
> line 527 "Parametrizing test functions" - may be worth having a simple
> example showing a combination using both (test data) parametrization
> and funcarg parametrization, to emphasise how they are differently
> useful. Using a database as an example of funcarg parametrization is
> good, maybe better than values like 1/2. I feel like parametrizing
> tests (test data) is probably the more common use case and it is a
> little buried amongst the heavy duty parametrized funcargs.
>
> line 598 "Basic ``pytest_generate_tests`` example" - I think this is
> not a very basic example! I think it is copied from parametrize.txt
> page, where it might make more sense. Here is what I would consider a
> basic example.
>
> # code
> def isSquare(n):
>     n = n ** 0.5
>     return int(n) == n
>
> # test file
> def pytest_generate_tests(metafunc):
>     squares = [1, 4, 9, 16, 25, 36, 49]
>     for n in range(1, 50):
>         expected = n in squares
>         if metafunc.function.__name__ == 'test_isSquare':
>             metafunc.addcall(id=n, funcargs=dict(n=n, expected=expected))
>
>
> def test_isSquare(n, expected):
>     assert isSquare(n) == expected
>
> Well, this is so trivial you might bundle it all into a single test,
> but it can be useful to have each case genuinely be a separate test.
> You could also shoe-horn this data into a parametrize decorator I
> suppose but it is nicer to have more space if your test data is more
> complicated, to explain it.
>
> I am starting to have a feeling that the way my project has been using
> generate_tests is not the way everyone else uses it. In our
> conftest.py one of the enterprising developers on the project (who got
> us all onto py.test initially) put this:
>
> def pytest_generate_tests(__multicall__, metafunc):
>     """Supports parametrised tests using generate_ fns.
>     Use multicall to call any other pytest_generate_tests hooks first.
>     If the test_ fn has a generate_ fn then call it with the metafunc
> to let it parametrise the test.
>     """
>     __multicall__.execute()
>     name = metafunc.function.__name__.replace('test_', 'generate_')
>     fn = getattr(metafunc.module, name, None)
>     if fn:
>         fn(metafunc)
>
> this means I can simplify my example above to:
>
> def generate_isSquare(metafunc):
>     squares = [1, 4, 9, 16, 25, 36, 49]
>     for n in range(1, 50):
>         expected = n in squares
>         metafunc.addcall(id=n, funcargs=dict(n=n, expected=expected))
>
> maybe this is a useful pattern for others? or maybe we're doing it
> wrong, I dunno :)
>
> in funcarg_compare.txt
> line 53 - (in old-style) "4. there is no way how you can make use of
> funcarg factories in xUnit setup methods."
>
> Is there an example of this? I would like to see it! This sounds like
> a way for people with existing xUnit style test suites to more easily
> convert to funcarg style.
>
> Maybe with all the parametrized test examples it is a good idea to
> show the verbose output, just to be more explicit about what is being
> generated.
>
> As an aside, there is a comment in example/markers.txt line 144 that
> "You can use the ``-k`` command line option to only run tests with
> names matching
> the given argument". Whether it is an oversight in the functionality
> or the docs, I have always found that -k also matches against markers
> (py.test.mark decorators). (Currently using pytest 2.2.3)
>
> in setup.txt
> line 65 'old = tmpdir.chdir()'
> - it's not really relevant to the example but I don't know what this
> does, and I couldn't find out, so it's just a bit distracting.
>
> thanks as always for providing this great library :)
>
> cheers
> Brianna
>
> --
> They've just been waiting in a mountain for the right moment:
> http://modernthings.org/



-- 
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