bpo-33462: Add __reversed__ to dict and dict views (GH-6827)

1 files changed, 66 insertions, 3 deletions

diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index 90c0a31..71fffe3 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -1021,7 +1021,7 @@ class DictTest(unittest.TestCase):
             it = iter(data)
             d = pickle.dumps(it, proto)
             it = pickle.loads(d)
-            self.assertEqual(sorted(it), sorted(data))
+            self.assertEqual(list(it), list(data))
 
             it = pickle.loads(d)
             try:
@@ -1031,7 +1031,7 @@ class DictTest(unittest.TestCase):
             d = pickle.dumps(it, proto)
             it = pickle.loads(d)
             del data[drop]
-            self.assertEqual(sorted(it), sorted(data))
+            self.assertEqual(list(it), list(data))
 
     def test_itemiterator_pickling(self):
         for proto in range(pickle.HIGHEST_PROTOCOL + 1):
@@ -1062,7 +1062,7 @@ class DictTest(unittest.TestCase):
             it = iter(data.values())
             d = pickle.dumps(it, proto)
             it = pickle.loads(d)
-            self.assertEqual(sorted(list(it)), sorted(list(data.values())))
+            self.assertEqual(list(it), list(data.values()))
 
             it = pickle.loads(d)
             drop = next(it)
@@ -1071,6 +1071,62 @@ class DictTest(unittest.TestCase):
             values = list(it) + [drop]
             self.assertEqual(sorted(values), sorted(list(data.values())))
 
+    def test_reverseiterator_pickling(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            data = {1:"a", 2:"b", 3:"c"}
+            it = reversed(data)
+            d = pickle.dumps(it, proto)
+            it = pickle.loads(d)
+            self.assertEqual(list(it), list(reversed(data)))
+
+            it = pickle.loads(d)
+            try:
+                drop = next(it)
+            except StopIteration:
+                continue
+            d = pickle.dumps(it, proto)
+            it = pickle.loads(d)
+            del data[drop]
+            self.assertEqual(list(it), list(reversed(data)))
+
+    def test_reverseitemiterator_pickling(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            data = {1:"a", 2:"b", 3:"c"}
+            # dictviews aren't picklable, only their iterators
+            itorg = reversed(data.items())
+            d = pickle.dumps(itorg, proto)
+            it = pickle.loads(d)
+            # note that the type of the unpickled iterator
+            # is not necessarily the same as the original.  It is
+            # merely an object supporting the iterator protocol, yielding
+            # the same objects as the original one.
+            # self.assertEqual(type(itorg), type(it))
+            self.assertIsInstance(it, collections.abc.Iterator)
+            self.assertEqual(dict(it), data)
+
+            it = pickle.loads(d)
+            drop = next(it)
+            d = pickle.dumps(it, proto)
+            it = pickle.loads(d)
+            del data[drop[0]]
+            self.assertEqual(dict(it), data)
+
+    def test_reversevaluesiterator_pickling(self):
+        for proto in range(pickle.HIGHEST_PROTOCOL):
+            data = {1:"a", 2:"b", 3:"c"}
+            # data.values() isn't picklable, only its iterator
+            it = reversed(data.values())
+            d = pickle.dumps(it, proto)
+            it = pickle.loads(d)
+            self.assertEqual(list(it), list(reversed(data.values())))
+
+            it = pickle.loads(d)
+            drop = next(it)
+            d = pickle.dumps(it, proto)
+            it = pickle.loads(d)
+            values = list(it) + [drop]
+            self.assertEqual(sorted(values), sorted(data.values()))
+
     def test_instance_dict_getattr_str_subclass(self):
         class Foo:
             def __init__(self, msg):
@@ -1222,6 +1278,13 @@ class DictTest(unittest.TestCase):
 
         self.assertRaises(RuntimeError, iter_and_mutate)
 
+    def test_reversed(self):
+        d = {"a": 1, "b": 2, "foo": 0, "c": 3, "d": 4}
+        del d["foo"]
+        r = reversed(d)
+        self.assertEqual(list(r), list('dcba'))
+        self.assertRaises(StopIteration, next, r)
+
     def test_dict_copy_order(self):
         # bpo-34320
         od = collections.OrderedDict([('a', 1), ('b', 2)])