bpo-41905: Add abc.update_abstractmethods() (GH-22485)
This function recomputes `cls.__abstractmethods__`.
Also update `@dataclass` to use it.
diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py
index b20103b..b31a469 100644
--- a/Lib/test/test_dataclasses.py
+++ b/Lib/test/test_dataclasses.py
@@ -4,6 +4,7 @@
from dataclasses import *
+import abc
import pickle
import inspect
import builtins
@@ -3332,6 +3333,42 @@
## replace(c, x=5)
+class TestAbstract(unittest.TestCase):
+ def test_abc_implementation(self):
+ class Ordered(abc.ABC):
+ @abc.abstractmethod
+ def __lt__(self, other):
+ pass
+
+ @abc.abstractmethod
+ def __le__(self, other):
+ pass
+
+ @dataclass(order=True)
+ class Date(Ordered):
+ year: int
+ month: 'Month'
+ day: 'int'
+
+ self.assertFalse(inspect.isabstract(Date))
+ self.assertGreater(Date(2020,12,25), Date(2020,8,31))
+
+ def test_maintain_abc(self):
+ class A(abc.ABC):
+ @abc.abstractmethod
+ def foo(self):
+ pass
+
+ @dataclass
+ class Date(A):
+ year: int
+ month: 'Month'
+ day: 'int'
+
+ self.assertTrue(inspect.isabstract(Date))
+ msg = 'class Date with abstract method foo'
+ self.assertRaisesRegex(TypeError, msg, Date)
+
if __name__ == '__main__':
unittest.main()