normalize exceptions passed to the __exit__ method #7853

In Python 2.x, exceptions in finally blocks are not normalized.  Since with
statements are implemented using finally blocks, ceval.c had to be tweaked to
distinguish between with finally blocks and normal ones.

A test for the finalization of generators containing with statements was also
added.

Lib/test/test_generators.py

@@ -1700,6 +1700,17 @@ And finalization:
 >>> del g
 exiting
 
+>>> class context(object):
+...    def __enter__(self): pass
+...    def __exit__(self, *args): print 'exiting'
+>>> def f():
+...     with context():
+...          yield
+>>> g = f()
+>>> g.next()
+>>> del g
+exiting
+
 
 GeneratorExit is not caught by except Exception:
 

Lib/test/test_with.py

@@ -361,7 +361,6 @@ class ExceptionalTestCase(unittest.TestCase, ContextmanagerAssertionMixin):
         self.assertAfterWithManagerInvariantsWithError(cm)
         self.assertAfterWithGeneratorInvariantsWithError(self.resource)
 
-    @unittest.expectedFailure
     def testExceptionNormalized(self):
         cm = mock_contextmanager_generator()
         def shouldThrow():