How to parameterize unittests

[Antoon Pardon]

Op 15-04-16 om 09:42 schreef Chris Angelico:
> On Fri, Apr 15, 2016 at 4:52 PM, Antoon Pardon
> <antoon.pardon at rece.vub.ac.be> wrote:
>> Op 14-04-16 om 17:05 schreef Steven D'Aprano:
>>> On Fri, 15 Apr 2016 12:08 am, Antoon Pardon wrote:
>>>
>>>> I have a unittest for my avltree module.
>>>>
>>>> Now I want this unittest to also run on a subclass of avltree.
>>>> How can I organise this, so that I can largely reuse the
>>>> original TestCase?
>>> class Test_AVLTree(unittest.TestCase):
>>>     tree = avltree
>>>
>>>     def test_empty_tree_is_false(self):
>>>         instance = self.tree()
>>>         self.assertFalse(instance)
>>>
>>>
>>> class Test_MySubclassTree(Test_AVLTree):
>>>     tree = My_Subclass_Tree
>> I see, that's going to be a lot of cut & pastes.
>> Thanks.
> Not really; the first class has all the tests, and the second one is
> literally just those two lines. It overrides 'tree' (accessed inside
> methods as 'self.tree'), and since all the tests are written to
> instantiate self.tree, they are effectively parameterized.

But the tests, at this moment, are not written to instantiate self.tree
but to call avltree directly. So I have to rewrite these tests. That
will IMO involve a lot of cut and paste.

-- 
Antoon.