unit testing - abstract test case using python unittest

Question

Is it possible to create an abstract TestCase, that will have some test_* methods, but this TestCase won't be called and those methods will only be used in subclasses? I think I am going to have one abstract TestCase in my test suite and it will be subclassed for a few different implementation of a single interface. This is why all test methods are the some, only one, internal method changes. How can I do it in elegant way?

Answer 1

I didn't quite understand what do you plan to do -- the rule of thumb is "not to be smart with tests" - just have them there, plain written.

But to achieve what you want, if you inherit from unittest.TestCase, whenever you call unittest.main() your "abstract" class will be executed - I think this is the situation you want to avoid.

Just do this: Create your "abstract" class inheriting from "object", not from TestCase. And for the actual "concrete" implementations, just use multiple inheritance: inherit from both unittest.TestCase and from your abstract class.

import unittest

class Abstract(object):
    def test_a(self):
        print "Running for class", self.__class__

class Test(Abstract, unittest.TestCase):
    pass

unittest.main()

update: reversed the inheritance order - Abstract first so that its defintions are not overriden by TestCase defaults, as well pointed in the comments bellow.