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authorEric V. Smith <ericvsmith@users.noreply.github.com>2021-05-03 03:24:53 -0400
committerGitHub <noreply@github.com>2021-05-03 03:24:53 -0400
commit99ad742ea913e421d012c1a623029eac31bdfe85 (patch)
treec4645c0b2590b0c8c082986e6fd390ab7304e80c /Lib/test
parent72720a2639368436da0981983549d000170623cc (diff)
downloadcpython-git-99ad742ea913e421d012c1a623029eac31bdfe85.tar.gz
bpo-44015: dataclasses should allow KW_ONLY to be specified only once per class (GH-25841)
bpo-44015: Raise a TypeError if KW_ONLY is specified more than once.
Diffstat (limited to 'Lib/test')
-rw-r--r--Lib/test/test_dataclasses.py77
1 files changed, 77 insertions, 0 deletions
diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py
index 16ee4c7705..8e645aeb4a 100644
--- a/Lib/test/test_dataclasses.py
+++ b/Lib/test/test_dataclasses.py
@@ -3699,6 +3699,83 @@ class TestKeywordArgs(unittest.TestCase):
self.assertEqual(c.b, 3)
self.assertEqual(c.c, 2)
+ def test_KW_ONLY_as_string(self):
+ @dataclass
+ class A:
+ a: int
+ _: 'dataclasses.KW_ONLY'
+ b: int
+ c: int
+ A(3, c=5, b=4)
+ msg = "takes 2 positional arguments but 4 were given"
+ with self.assertRaisesRegex(TypeError, msg):
+ A(3, 4, 5)
+
+ def test_KW_ONLY_twice(self):
+ msg = "'Y' is KW_ONLY, but KW_ONLY has already been specified"
+
+ with self.assertRaisesRegex(TypeError, msg):
+ @dataclass
+ class A:
+ a: int
+ X: KW_ONLY
+ Y: KW_ONLY
+ b: int
+ c: int
+
+ with self.assertRaisesRegex(TypeError, msg):
+ @dataclass
+ class A:
+ a: int
+ X: KW_ONLY
+ b: int
+ Y: KW_ONLY
+ c: int
+
+ with self.assertRaisesRegex(TypeError, msg):
+ @dataclass
+ class A:
+ a: int
+ X: KW_ONLY
+ b: int
+ c: int
+ Y: KW_ONLY
+
+ # But this usage is okay, since it's not using KW_ONLY.
+ @dataclass
+ class A:
+ a: int
+ _: KW_ONLY
+ b: int
+ c: int = field(kw_only=True)
+
+ # And if inheriting, it's okay.
+ @dataclass
+ class A:
+ a: int
+ _: KW_ONLY
+ b: int
+ c: int
+ @dataclass
+ class B(A):
+ _: KW_ONLY
+ d: int
+
+ # Make sure the error is raised in a derived class.
+ with self.assertRaisesRegex(TypeError, msg):
+ @dataclass
+ class A:
+ a: int
+ _: KW_ONLY
+ b: int
+ c: int
+ @dataclass
+ class B(A):
+ X: KW_ONLY
+ d: int
+ Y: KW_ONLY
+
+
def test_post_init(self):
@dataclass
class A: