test-ctxmanager: fix Python 2.6 compatibility problem

tests/test-ctxmanager.py

@@ -1,77 +1,79 b''
 from __future__ import absolute_import
 
 import silenttestrunner
 import unittest
 
 from mercurial.util import ctxmanager
 
 class contextmanager(object):
     def __init__(self, name, trace):
         self.name = name
         self.entered = False
         self.exited = False
         self.trace = trace
 
     def __enter__(self):
         self.entered = True
         self.trace(('enter', self.name))
         return self
 
     def __exit__(self, exc_type, exc_val, exc_tb):
         self.exited = exc_type, exc_val, exc_tb
         self.trace(('exit', self.name))
 
     def __repr__(self):
         return '<ctx %r>' % self.name
 
 class ctxerror(Exception):
     pass
 
 class raise_on_enter(contextmanager):
     def __enter__(self):
         self.trace(('raise', self.name))
         raise ctxerror(self.name)
 
 class raise_on_exit(contextmanager):
     def __exit__(self, exc_type, exc_val, exc_tb):
         self.trace(('raise', self.name))
         raise ctxerror(self.name)
 
 def ctxmgr(name, trace):
     return lambda: contextmanager(name, trace)
 
 class test_ctxmanager(unittest.TestCase):
     def test_basics(self):
         trace = []
         addtrace = trace.append
         with ctxmanager(ctxmgr('a', addtrace), ctxmgr('b', addtrace)) as c:
             a, b = c.enter()
             c.atexit(addtrace, ('atexit', 'x'))
             c.atexit(addtrace, ('atexit', 'y'))
         self.assertEqual(trace, [('enter', 'a'), ('enter', 'b'),
                                  ('atexit', 'y'), ('atexit', 'x'),
                                  ('exit', 'b'), ('exit', 'a')])
 
     def test_raise_on_enter(self):
         trace = []
         addtrace = trace.append
-        with self.assertRaises(ctxerror):
+        def go():
             with ctxmanager(ctxmgr('a', addtrace),
                            lambda: raise_on_enter('b', addtrace)) as c:
                 c.enter()
                 addtrace('unreachable')
+        self.assertRaises(ctxerror, go)
         self.assertEqual(trace, [('enter', 'a'), ('raise', 'b'), ('exit', 'a')])
 
     def test_raise_on_exit(self):
         trace = []
         addtrace = trace.append
-        with self.assertRaises(ctxerror):
+        def go():
             with ctxmanager(ctxmgr('a', addtrace),
                            lambda: raise_on_exit('b', addtrace)) as c:
                 c.enter()
                 addtrace('running')
+        self.assertRaises(ctxerror, go)
         self.assertEqual(trace, [('enter', 'a'), ('enter', 'b'), 'running',
                                  ('raise', 'b'), ('exit', 'a')])
 
 if __name__ == '__main__':
     silenttestrunner.main(__name__)