[TIP] Hint on TestClass

[Thijs Engels]

Holger,

Thank you very much for your response, I have been able to make progress
on this now.

This actually brings me to a question on the same topic. What is the
meaning of classes in py.test (over just functions)? It is merely for me
as the user to have an overview? Asking this question with
parametrization in mind. I thought that a class would be considered a
suite with a collection of tests which should be run as a group, short
example the file with tests:

class TestSession:
    def test_id(self, session):
        assert isinstance(session.id, int)
        assert session.id > 0

    def test_date(self, session):
        assert isinstance(session.delivery_date, date)
        assert session.delivery_date > date(2010, 12, 31)

The session parameter is parametrized via the indirect option combined
with the factory function as indicated in your earlier response
(currently limited to three sessions).

Running this results in this (verbose) output:

test_universe.py:4: TestSession.test_id[1] PASSED
test_universe.py:4: TestSession.test_id[2] PASSED
test_universe.py:4: TestSession.test_id[3] PASSED
test_universe.py:8: TestSession.test_date[1] PASSED
test_universe.py:8: TestSession.test_date[2] PASSED
test_universe.py:8: TestSession.test_date[3] PASSED

As the session information is retrieved from a database I would prefer
to first do all tests on session object 1, before starting on session 2,
hence the output I would like is:

test_universe.py:4: TestSession.test_id[1] PASSED
test_universe.py:8: TestSession.test_date[1] PASSED
test_universe.py:4: TestSession.test_id[2] PASSED
test_universe.py:8: TestSession.test_date[2] PASSED
test_universe.py:4: TestSession.test_id[3] PASSED
test_universe.py:8: TestSession.test_date[3] PASSED

As stated earlier I thought this could be done via a TestClass, which
need the additional self parameter which shows up in the debug output
for failed tests as well. Is there a way to construct (parametrized)
test suites?

Kind regards,

Thijs

On Thu, Jul 12, 2012, at 06:27, holger krekel wrote:
> Hi Thijs,
> 
> On Wed, Jul 11, 2012 at 16:26 +0200, Thijs Engels wrote:
> > Hello all,
> > 
> > I am currently running multiple tests (using py.test) on a series of
> > objects which are relatively expensive to retrieve. My thinking was to
> > group the tests on the same object into one class, potentially using the
> > setup/teardown at class level to retrieve the object under test.
> 
> This is a classic use case for "funcargs".  See here for a basic example:
> 
> http://pytest.org/latest/example/parametrize.html#deferring-the-setup-of-parametrized-resources
> 
> In addition, you probably want to extend the setup of resources by
> using the request.cached_setup() helper like so:
> 
>     def pytest_funcarg__db(request):
>         if request.param == "d1":
>             return request.cached_setup(setup=DB1, scope="session",
>                                         extrakey=request.param)
>         ...
> 
> This will make sure that your setup function (in this case the DB1 class)
> will only be called once per session.  Other scopes are "class" or
> "module".
>     
> > As mentioned there is a series of these objects, hence I would like to
> > parametrize the class holding all the individual tests. Via the search
> > on the py.test I actually landed on a page which seems to describe
> > exactly what I am after:
> > http://pytest.org/dev/example/resources_attic.html, although I could not
> > complete figure out the given example with self.db.
> 
> Not sure how you could find "attic" documents but this is not a valid
> suggestion these days. 
> 
> best,
> holger
> 
> 
> > 
> > This is about what I hoping to archive:
> >   Use parametrize to run the test in TestSession for a list of
> >   session_ids.
> > 
> > TestSession:
> >   def __init__(self, session_id):
> >     self.session = expensive_database_query(session_id)
> > 
> >   def test_session_id():
> >     assert session.id > 0
> > 
> >   def test_session_date():
> >     assert session.date >= date(2012, 1, 1)
> > 
> >   def test_periods():
> >     assert periods in range(1, 26)
> > 
> > Is the resource_attic link indeed describing what I am after?
> > 
> > Thijs
> > 
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> >