bpo-36144: Update MappingProxyType with PEP 584's operators (#18814)

We make `|=` raise TypeError, since it would be surprising if `C.__dict__ |= {'x': 0}` silently did nothing, while `C.__dict__.update({'x': 0})` is an error.

1 files changed, 19 insertions, 0 deletions

diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index 7b45b7a..544c91b 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -622,8 +622,11 @@ class MappingProxyTests(unittest.TestCase):
         self.assertEqual(attrs, {
              '__contains__',
              '__getitem__',
+             '__ior__',
              '__iter__',
              '__len__',
+             '__or__',
+             '__ror__',
              'copy',
              'get',
              'items',
@@ -774,6 +777,22 @@ class MappingProxyTests(unittest.TestCase):
         self.assertEqual(view['key1'], 70)
         self.assertEqual(copy['key1'], 27)
 
+    def test_union(self):
+        mapping = {'a': 0, 'b': 1, 'c': 2}
+        view = self.mappingproxy(mapping)
+        with self.assertRaises(TypeError):
+            view | [('r', 2), ('d', 2)]
+        with self.assertRaises(TypeError):
+            [('r', 2), ('d', 2)] | view
+        with self.assertRaises(TypeError):
+            view |= [('r', 2), ('d', 2)]
+        other = {'c': 3, 'p': 0}
+        self.assertDictEqual(view | other, {'a': 0, 'b': 1, 'c': 3, 'p': 0})
+        self.assertDictEqual(other | view, {'c': 2, 'p': 0, 'a': 0, 'b': 1})
+        self.assertEqual(view, {'a': 0, 'b': 1, 'c': 2})
+        self.assertDictEqual(mapping, {'a': 0, 'b': 1, 'c': 2})
+        self.assertDictEqual(other, {'c': 3, 'p': 0})
+
 
 class ClassCreationTests(unittest.TestCase):