- 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).

Lib/test/test_defaultdict.py

@@ -0,0 +1,135 @@
+"""Unit tests for collections.defaultdict."""
+
+import os
+import copy
+import tempfile
+import unittest
+
+from collections import defaultdict
+
+def foobar():
+    return list
+
+class TestDefaultDict(unittest.TestCase):
+
+    def test_basic(self):
+        d1 = defaultdict()
+        self.assertEqual(d1.default_factory, None)
+        d1.default_factory = list
+        d1[12].append(42)
+        self.assertEqual(d1, {12: [42]})
+        d1[12].append(24)
+        self.assertEqual(d1, {12: [42, 24]})
+        d1[13]
+        d1[14]
+        self.assertEqual(d1, {12: [42, 24], 13: [], 14: []})
+        self.assert_(d1[12] is not d1[13] is not d1[14])
+        d2 = defaultdict(list, foo=1, bar=2)
+        self.assertEqual(d2.default_factory, list)
+        self.assertEqual(d2, {"foo": 1, "bar": 2})
+        self.assertEqual(d2["foo"], 1)
+        self.assertEqual(d2["bar"], 2)
+        self.assertEqual(d2[42], [])
+        self.assert_("foo" in d2)
+        self.assert_("foo" in d2.keys())
+        self.assert_("bar" in d2)
+        self.assert_("bar" in d2.keys())
+        self.assert_(42 in d2)
+        self.assert_(42 in d2.keys())
+        self.assert_(12 not in d2)
+        self.assert_(12 not in d2.keys())
+        d2.default_factory = None
+        self.assertEqual(d2.default_factory, None)
+        try:
+            d2[15]
+        except KeyError, err:
+            self.assertEqual(err.args, (15,))
+        else:
+            self.fail("d2[15] didn't raise KeyError")
+
+    def test_missing(self):
+        d1 = defaultdict()
+        self.assertRaises(KeyError, d1.__missing__, 42)
+        d1.default_factory = list
+        self.assertEqual(d1.__missing__(42), [])
+
+    def test_repr(self):
+        d1 = defaultdict()
+        self.assertEqual(d1.default_factory, None)
+        self.assertEqual(repr(d1), "defaultdict(None, {})")
+        d1[11] = 41
+        self.assertEqual(repr(d1), "defaultdict(None, {11: 41})")
+        d2 = defaultdict(0)
+        self.assertEqual(d2.default_factory, 0)
+        d2[12] = 42
+        self.assertEqual(repr(d2), "defaultdict(0, {12: 42})")
+        def foo(): return 43
+        d3 = defaultdict(foo)
+        self.assert_(d3.default_factory is foo)
+        d3[13]
+        self.assertEqual(repr(d3), "defaultdict(%s, {13: 43})" % repr(foo))
+
+    def test_print(self):
+        d1 = defaultdict()
+        def foo(): return 42
+        d2 = defaultdict(foo, {1: 2})
+        # NOTE: We can't use tempfile.[Named]TemporaryFile since this
+        # code must exercise the tp_print C code, which only gets
+        # invoked for *real* files.
+        tfn = tempfile.mktemp()
+        try:
+            f = open(tfn, "w+")
+            try:
+                print >>f, d1
+                print >>f, d2
+                f.seek(0)
+                self.assertEqual(f.readline(), repr(d1) + "\n")
+                self.assertEqual(f.readline(), repr(d2) + "\n")
+            finally:
+                f.close()
+        finally:
+            os.remove(tfn)
+
+    def test_copy(self):
+        d1 = defaultdict()
+        d2 = d1.copy()
+        self.assertEqual(type(d2), defaultdict)
+        self.assertEqual(d2.default_factory, None)
+        self.assertEqual(d2, {})
+        d1.default_factory = list
+        d3 = d1.copy()
+        self.assertEqual(type(d3), defaultdict)
+        self.assertEqual(d3.default_factory, list)
+        self.assertEqual(d3, {})
+        d1[42]
+        d4 = d1.copy()
+        self.assertEqual(type(d4), defaultdict)
+        self.assertEqual(d4.default_factory, list)
+        self.assertEqual(d4, {42: []})
+        d4[12]
+        self.assertEqual(d4, {42: [], 12: []})
+
+    def test_shallow_copy(self):
+        d1 = defaultdict(foobar, {1: 1})
+        d2 = copy.copy(d1)
+        self.assertEqual(d2.default_factory, foobar)
+        self.assertEqual(d2, d1)
+        d1.default_factory = list
+        d2 = copy.copy(d1)
+        self.assertEqual(d2.default_factory, list)
+        self.assertEqual(d2, d1)
+
+    def test_deep_copy(self):
+        d1 = defaultdict(foobar, {1: [1]})
+        d2 = copy.deepcopy(d1)
+        self.assertEqual(d2.default_factory, foobar)
+        self.assertEqual(d2, d1)
+        self.assert_(d1[1] is not d2[1])
+        d1.default_factory = list
+        d2 = copy.deepcopy(d1)
+        self.assertEqual(d2.default_factory, list)
+        self.assertEqual(d2, d1)
+
+
+if __name__ == "__main__":
+    unittest.main()