Simplify test case example code

pep-0399.txt

@@ -116,8 +116,7 @@ possible.
 As an example, to write tests which exercise both the pure Python and
 C accelerated versions of a module, a basic idiom can be followed::
 
-    import collections.abc
-    from test.support import import_fresh_module, run_unittest
+    from test.support import import_fresh_module
     import unittest
 
     c_heapq = import_fresh_module('heapq', fresh=['_heapq'])
@@ -126,30 +125,17 @@ C accelerated versions of a module, a basic idiom can be followed::
 
     class ExampleTest:
 
-        def test_heappop_exc_for_non_MutableSequence(self):
-            # Raise TypeError when heap is not a
-            # collections.abc.MutableSequence.
-            class Spam:
-                """Test class lacking many ABC-required methods
-                (e.g., pop())."""
-                def __len__(self):
-                    return 0
-
-            heap = Spam()
-            self.assertIsInstance(heap, collections.abc.MutableSequence)
-            with self.assertRaises(TypeError):
-                self.heapq.heappop(heap)
+        def test_example(self):
+            self.assertTrue(hasattr(self.module, 'heapify'))
 
 
     class PyExampleTest(ExampleTest, unittest.TestCase):
-        """Test with just the pure Python code."""
-        heapq = py_heapq
+        module = py_heapq
 
 
     @unittest.skipUnless(c_heapq, 'requires the C _heapq module')
     class CExampleTest(ExampleTest, unittest.TestCase):
-        """Test using the accelerated code."""
-        heapq = c_heapq
+        module = c_heapq
 
 
     if __name__ == '__main__':