diff --git a/Lib/test/test_iterlen.py b/Lib/test/test_iterlen.py
--- a/Lib/test/test_iterlen.py
+++ b/Lib/test/test_iterlen.py
@@ -50,7 +50,7 @@
 n = 10
 
 
-class TestInvariantWithoutMutations(unittest.TestCase):
+class TestInvariantWithoutMutations:
 
     def test_invariant(self):
         it = self.it
@@ -77,64 +77,64 @@
 
 ## ------- Concrete Type Tests -------
 
-class TestRepeat(TestInvariantWithoutMutations):
+class TestRepeat(TestInvariantWithoutMutations, unittest.TestCase):
 
     def setUp(self):
         self.it = repeat(None, n)
 
-class TestXrange(TestInvariantWithoutMutations):
+class TestXrange(TestInvariantWithoutMutations, unittest.TestCase):
 
     def setUp(self):
         self.it = iter(range(n))
 
-class TestXrangeCustomReversed(TestInvariantWithoutMutations):
+class TestXrangeCustomReversed(TestInvariantWithoutMutations, unittest.TestCase):
 
     def setUp(self):
         self.it = reversed(range(n))
 
-class TestTuple(TestInvariantWithoutMutations):
+class TestTuple(TestInvariantWithoutMutations, unittest.TestCase):
 
     def setUp(self):
         self.it = iter(tuple(range(n)))
 
 ## ------- Types that should not be mutated during iteration -------
 
-class TestDeque(TestTemporarilyImmutable):
+class TestDeque(TestTemporarilyImmutable, unittest.TestCase):
 
     def setUp(self):
         d = deque(range(n))
         self.it = iter(d)
         self.mutate = d.pop
 
-class TestDequeReversed(TestTemporarilyImmutable):
+class TestDequeReversed(TestTemporarilyImmutable, unittest.TestCase):
 
     def setUp(self):
         d = deque(range(n))
         self.it = reversed(d)
         self.mutate = d.pop
 
-class TestDictKeys(TestTemporarilyImmutable):
+class TestDictKeys(TestTemporarilyImmutable, unittest.TestCase):
 
     def setUp(self):
         d = dict.fromkeys(range(n))
         self.it = iter(d)
         self.mutate = d.popitem
 
-class TestDictItems(TestTemporarilyImmutable):
+class TestDictItems(TestTemporarilyImmutable, unittest.TestCase):
 
     def setUp(self):
         d = dict.fromkeys(range(n))
         self.it = iter(d.items())
         self.mutate = d.popitem
 
-class TestDictValues(TestTemporarilyImmutable):
+class TestDictValues(TestTemporarilyImmutable, unittest.TestCase):
 
     def setUp(self):
         d = dict.fromkeys(range(n))
         self.it = iter(d.values())
         self.mutate = d.popitem
 
-class TestSet(TestTemporarilyImmutable):
+class TestSet(TestTemporarilyImmutable, unittest.TestCase):
 
     def setUp(self):
         d = set(range(n))
@@ -143,7 +143,7 @@
 
 ## ------- Types that can mutate during iteration -------
 
-class TestList(TestInvariantWithoutMutations):
+class TestList(TestInvariantWithoutMutations, unittest.TestCase):
 
     def setUp(self):
         self.it = iter(range(n))
@@ -163,7 +163,7 @@
         self.assertEqual(length_hint(it), 0)
 
 
-class TestListReversed(TestInvariantWithoutMutations):
+class TestListReversed(TestInvariantWithoutMutations, unittest.TestCase):
 
     def setUp(self):
         self.it = reversed(range(n))
@@ -225,23 +225,5 @@
         self.assertEqual(list(NoneLengthHint()), list(range(10)))
 
 
-def test_main():
-    unittests = [
-        TestRepeat,
-        TestXrange,
-        TestXrangeCustomReversed,
-        TestTuple,
-        TestDeque,
-        TestDequeReversed,
-        TestDictKeys,
-        TestDictItems,
-        TestDictValues,
-        TestSet,
-        TestList,
-        TestListReversed,
-        TestLengthHintExceptions,
-    ]
-    support.run_unittest(*unittests)
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()