- Patch 1433928:
- The copy module now "copies" function objects (as atomic objects).
- dict.__getitem__ now looks for a __missing__ hook before raising
KeyError.
- Added a new type, defaultdict, to the collections module.
This uses the new __missing__ hook behavior added to dict (see above).
diff --git a/Lib/test/test_userdict.py b/Lib/test/test_userdict.py
index 2d5fa03..a4b7de4 100644
--- a/Lib/test/test_userdict.py
+++ b/Lib/test/test_userdict.py
@@ -148,6 +148,55 @@
self.assertEqual(t.popitem(), ("x", 42))
self.assertRaises(KeyError, t.popitem)
+ def test_missing(self):
+ # Make sure UserDict doesn't have a __missing__ method
+ self.assertEqual(hasattr(UserDict, "__missing__"), False)
+ # Test several cases:
+ # (D) subclass defines __missing__ method returning a value
+ # (E) subclass defines __missing__ method raising RuntimeError
+ # (F) subclass sets __missing__ instance variable (no effect)
+ # (G) subclass doesn't define __missing__ at a all
+ class D(UserDict.UserDict):
+ def __missing__(self, key):
+ return 42
+ d = D({1: 2, 3: 4})
+ self.assertEqual(d[1], 2)
+ self.assertEqual(d[3], 4)
+ self.assert_(2 not in d)
+ self.assert_(2 not in d.keys())
+ self.assertEqual(d[2], 42)
+ class E(UserDict.UserDict):
+ def __missing__(self, key):
+ raise RuntimeError(key)
+ e = E()
+ try:
+ e[42]
+ except RuntimeError, err:
+ self.assertEqual(err.args, (42,))
+ else:
+ self.fail_("e[42] didn't raise RuntimeError")
+ class F(UserDict.UserDict):
+ def __init__(self):
+ # An instance variable __missing__ should have no effect
+ self.__missing__ = lambda key: None
+ UserDict.UserDict.__init__(self)
+ f = F()
+ try:
+ f[42]
+ except KeyError, err:
+ self.assertEqual(err.args, (42,))
+ else:
+ self.fail_("f[42] didn't raise KeyError")
+ class G(UserDict.UserDict):
+ pass
+ g = G()
+ try:
+ g[42]
+ except KeyError, err:
+ self.assertEqual(err.args, (42,))
+ else:
+ self.fail_("g[42] didn't raise KeyError")
+
##########################
# Test Dict Mixin