Multi with statement

Lib/test/test_with.py

 #!/usr/bin/env python
 
 """Unit tests for the with statement specified in PEP 343."""
 
 
 __author__ = "Mike Bland"
 __email__ = "mbland at acm dot org"
 
 import sys
 import unittest
@@ skipping 636 matching lines @@
             def __exit__(self, t, v, tb): return False
         try:
             with EuropeanSwallow():
                 1/0
         except ZeroDivisionError:
             pass
         else:
             self.fail("ZeroDivisionError should have been raised")
 
 
+class NestedWith(unittest.TestCase):

[Benjamin, 2009/05/02 18:22:06]

You should test that the second's __exit__ is called even if the first one
raises.

[Georg, 2009/05/02 18:48:00]

Done.

+
+    class Dummy(object):
+        def __init__(self, value=None):·
+            if value is None:
+                value = self
+            self.value = value
+            self.enter_called = False
+            self.exit_called = False
+
+        def __enter__(self):
+            self.enter_called = True
+            return self.value
+
+        def __exit__(self, *exc_info):·
+            self.exit_called = True
+
+    class CtorThrows(object):
+        def __init__(self): raise RuntimeError()
+
+    class EnterThrows(object):
+        def __enter__(self): raise RuntimeError()
+        def __exit__(self, *exc_info): pass
+
+    def testNoExceptions(self):
+        with self.Dummy() as a, self.Dummy() as b:
+            self.assertTrue(a.enter_called)
+            self.assertTrue(b.enter_called)
+        self.assertTrue(a.exit_called)
+        self.assertTrue(b.exit_called)
+
+    def testExceptionInExprList(self):
+        try:
+            with self.Dummy() as a, self.CtorThrows():
+                pass
+        except:
+            pass
+        self.assertTrue(a.enter_called)
+        self.assertTrue(a.exit_called)
+
+    def testExceptionInEnter(self):
+        try:
+            with self.Dummy() as a, self.EnterThrows():
+                pass
+        except:
+            pass
+        self.assertTrue(a.enter_called)
+        self.assertTrue(a.exit_called)
+········
+    def testEnterReturnsTuple(self):
+        with self.Dummy(value=(1,2)) as (a1, a2), \
+             self.Dummy(value=(10, 20)) as (b1, b2):
+            self.assertEquals(1, a1)
+            self.assertEquals(2, a2)
+            self.assertEquals(10, b1)
+            self.assertEquals(20, b2)
+
 def test_main():
     run_unittest(FailureTestCase, NonexceptionalTestCase,
                  NestedNonexceptionalTestCase, ExceptionalTestCase,
                  NonLocalFlowControlTestCase,
                  AssignmentTargetTestCase,
-                 ExitSwallowsExceptionTestCase)
+                 ExitSwallowsExceptionTestCase,
+                 NestedWith)
 
 
 if __name__ == '__main__':
     test_main()