unit testing class hierarchies

[Peter Otten]

Ulrich Eckhardt wrote:

> Am 02.10.2012 16:06, schrieb Thomas Bach:
>> On Tue, Oct 02, 2012 at 02:27:11PM +0200, Ulrich Eckhardt wrote:
>>> As you see, the code for test_base() is redundant, so the idea is to
>>> move it to a baseclass:
>>>
>>> class TestBase(unittest.TestCase):
>>>      def test_base(self):
>>>          ...
>>>
>>> class TestD1(TestBase):
>>>      def test_r(self):
>>>          ...
>>>      def test_s(self):
>>>          ...
>>>
>>> class TestD2(TestBase):
>>>      def test_x(self):
>>>          ...
>>>      def test_y(self):
>>>          ...
>>
>> Could you provide more background? How do you avoid that test_base()
>> runs in TestD1 or TestD2?
> 
> Sorry, there's a misunderstanding: I want test_base() to be run as part
> of both TestD1 and TestD2, because it tests basic functions provided by
> both classes D1 and D2. The instances of D1 and D2 are created in
> TestD1.setUp and TestD2.setUp and then used by all tests. There is no
> possible implementation creating such an instance for TestBase, since
> the baseclass is abstract.
> 
> Last edit for today, I hope that makes my intentions clear...
> 
> ;)

Ceterum censeo baseclassinem esse delendam ;)

$ cat test_shared.py
import unittest

class Shared(unittest.TestCase):
    def test_shared(self):
        pass

class D1(Shared):
    def test_d1_only(self):
        pass

class D2(Shared):
    def test_d2_only(self):
        pass

del Shared

unittest.main()

$ python test_shared.py -v
test_d1_only (__main__.D1) ... ok
test_shared (__main__.D1) ... ok
test_d2_only (__main__.D2) ... ok
test_shared (__main__.D2) ... ok

----------------------------------------------------------------------
Ran 4 tests in 0.000s

OK
$