I am currently learning python in preperation for a class over the summer and have gotten started by implementing different types of heaps and priority based data structures.

I began to write a unit test suite for the project but ran into difficulties into creating a generic unit test that only tests the interface and is oblivious of the actual implementation.

I am wondering if it is possible to do something like this..

suite = HeapTestSuite(BinaryHeap())
suite.run()
suite = HeapTestSuite(BinomialHeap())
suite.run()

What I am currently doing just feels... wrong (multiple inheritance? ACK!)..

class TestHeap:def reset_heap(self):self.heap = Nonedef test_insert(self):self.reset_heap()#test that insert doesnt throw an exception...for x in self.inseq:self.heap.insert(x)def test_delete(self):#assert we get the first value we put inself.reset_heap()self.heap.insert(5)self.assertEquals(5, self.heap.delete_min())#harder test. put in sequence in and check that it comes out rightself.reset_heap()for x in self.inseq:self.heap.insert(x)for x in xrange(len(self.inseq)):val = self.heap.delete_min()self.assertEquals(val, x)class BinaryHeapTest(TestHeap, unittest.TestCase):def setUp(self):self.inseq = range(99, -1, -1)self.heap = BinaryHeap()def reset_heap(self):self.heap = BinaryHeap()class BinomialHeapTest(TestHeap, unittest.TestCase):def setUp(self):self.inseq = range(99, -1, -1)self.heap = BinomialHeap()def reset_heap(self):self.heap = BinomialHeap()if __name__ == '__main__':unittest.main()

I personally like nose test generation more for this sort of thing. I'd then write it like:

# They happen to all be simple callable factories, if they weren't you could put
# a function in here:
make_heaps = [BinaryHeap, BinomialHeap]def test_heaps():for make_heap in make_heaps:for checker in checkers: # we'll set checkers lateryield checker, make_heapdef check_insert(make_heap):heap = make_heap()for x in range(99, -1, -1):heap.insert(x)# def check_delete_min etc.checkers = [valuefor name, value in sorted(globals().items())if name.startswith('check_')]