bpo-46445: Cover multiple inheritance of TypedDict in test_typing (GH-30719)

(cherry picked from commit 65b88d5e01)

Co-authored-by: Nikita Sobolev <mail@sobolevn.me>

Lib/test/test_typing.py

@@ -19,7 +19,6 @@
 from typing import is_typeddict
 from typing import no_type_check, no_type_check_decorator
 from typing import Type
-from typing import NewType
 from typing import NamedTuple, TypedDict
 from typing import IO, TextIO, BinaryIO
 from typing import Pattern, Match
@@ -4302,6 +4301,93 @@ class Cat(Animal):
             'voice': str,
         }
 
+    def test_multiple_inheritance(self):
+        class One(TypedDict):
+            one: int
+        class Two(TypedDict):
+            two: str
+        class Untotal(TypedDict, total=False):
+            untotal: str
+        Inline = TypedDict('Inline', {'inline': bool})
+        class Regular:
+            pass
+
+        class Child(One, Two):
+            child: bool
+        self.assertEqual(
+            Child.__required_keys__,
+            frozenset(['one', 'two', 'child']),
+        )
+        self.assertEqual(
+            Child.__optional_keys__,
+            frozenset([]),
+        )
+        self.assertEqual(
+            Child.__annotations__,
+            {'one': int, 'two': str, 'child': bool},
+        )
+
+        class ChildWithOptional(One, Untotal):
+            child: bool
+        self.assertEqual(
+            ChildWithOptional.__required_keys__,
+            frozenset(['one', 'child']),
+        )
+        self.assertEqual(
+            ChildWithOptional.__optional_keys__,
+            frozenset(['untotal']),
+        )
+        self.assertEqual(
+            ChildWithOptional.__annotations__,
+            {'one': int, 'untotal': str, 'child': bool},
+        )
+
+        class ChildWithTotalFalse(One, Untotal, total=False):
+            child: bool
+        self.assertEqual(
+            ChildWithTotalFalse.__required_keys__,
+            frozenset(['one']),
+        )
+        self.assertEqual(
+            ChildWithTotalFalse.__optional_keys__,
+            frozenset(['untotal', 'child']),
+        )
+        self.assertEqual(
+            ChildWithTotalFalse.__annotations__,
+            {'one': int, 'untotal': str, 'child': bool},
+        )
+
+        class ChildWithInlineAndOptional(Untotal, Inline):
+            child: bool
+        self.assertEqual(
+            ChildWithInlineAndOptional.__required_keys__,
+            frozenset(['inline', 'child']),
+        )
+        self.assertEqual(
+            ChildWithInlineAndOptional.__optional_keys__,
+            frozenset(['untotal']),
+        )
+        self.assertEqual(
+            ChildWithInlineAndOptional.__annotations__,
+            {'inline': bool, 'untotal': str, 'child': bool},
+        )
+
+        wrong_bases = [
+            (One, Regular),
+            (Regular, One),
+            (One, Two, Regular),
+            (Inline, Regular),
+            (Untotal, Regular),
+        ]
+        for bases in wrong_bases:
+            with self.subTest(bases=bases):
+                with self.assertRaisesRegex(
+                    TypeError,
+                    'cannot inherit from both a TypedDict type and a non-TypedDict',
+                ):
+                    class Wrong(*bases):
+                        pass
+
     def test_is_typeddict(self):
         assert is_typeddict(Point2D) is True
         assert is_typeddict(Union[str, int]) is False