On Feb 6, 11:53 am, "Nicolas M. Thiery" <nicolas.thi...@u-psud.fr>
wrote:
> Dear all,
<SNIP>
HI Nicolas,
> I just want to mention that I am precisely setting up a standardized
> way in the category framework for setting up this kind of generic
> tests. See in particular Sets? after installing the sage-combinat
> patches. Comments, suggestions and reviews most welcome!
>
> General idea: Imagine you have just implemented a parent P in the
> category SemiGroups(). Here, I'll just take the example of semi-group
> provided by the category:
>
> sage: P = SemiGroups().example()
> The trivial semigroup with a*b == a
>
> (for the record, this line above is fake, but it will actually work
> very soon; by the way: should this be called a_parent() or something else?)
>
> Now, you want to run generic checks on P. You can just do:
>
> sage: P.check(verbose = True)
> running test_an_element ...
> running test_some_elements ...
> running test_pickling ...
> running test_element_pickling ...
> running test_associativity ...
>
> If you want to run individual tests, you can do directly:
>
> sage: P.test_associativity()
>
> In case something goes wrong (which is the case currently, bummer),
> you get a traceback:
>
> sage: P.check()
> PicklingError Traceback (most recent call
> last)
> ...
> PicklingError: Can't pickle ...
>
> Let's open the hood. Here is the default implementation for
> test_associativity, which is provided by the SemiGroups category:
>
> def test_associativity(self, tester = trivial_tester):
> tester.assert_(all((x * y) * z == x * (y * z)
> for x in self.some_elements()
> for y in self.some_elements()
> for z in self.some_elements()))
>
> The tester gadget is a plugin mechanism so that in the long run one
> will be able to ask for other treatment of errors, like issuing
> warnings, counting the errors, or using the test case within a
> standard testunit framework.
>
> some_elements is a method, similar to an_element, which returns a
> "good" collection of elements, typically to run tests upon. What
> "good" means is left upon the parent implementer, but there are some
> reasonable defaults (like returning all the elements for a finite
> group, or all the basis elements for a finite dimensional vector
> space). Of course, there should be an easy way for the user to specify
> on which sets he wants to run the tests, so as to use this method for
> proofs.
>
> P.check() (should it be P.test()?) just calls every methods of the
> parent called test* (parallel to what is done in testunit). So the
> parent may very well add extra test cases, or override some of them
> with more efficient ones.
>
> To come back to __hash__, a sane default might be to check that
> __hash__ at least returns something different for each element in
> P.some_elements() (I am not sure about the specs of __hash__; should
> we also check that __hash__ returns an int?).
>
> Best regards,
> Nicolas
This looks *very* cool and useful. Any idea when it will be ready and
how much of it has a dependency on code in Sage-combinat not yet
merged into Sage?
Cheers,
Michael
> --
> Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>http://Nicolas.Thiery.name/
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