gh-90172: add test for functools.singledispatch on Union types with None type (#92174)
Signed-off-by: prwatson <prwatson@redhat.com>
Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index e3c0656..382e7db 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -2792,6 +2792,49 @@ def _(arg: int | float):
self.assertEqual(f(1), "types.UnionType")
self.assertEqual(f(1.0), "types.UnionType")
+ def test_union_conflict(self):
+ @functools.singledispatch
+ def f(arg):
+ return "default"
+
+ @f.register
+ def _(arg: typing.Union[str, bytes]):
+ return "typing.Union"
+
+ @f.register
+ def _(arg: int | str):
+ return "types.UnionType"
+
+ self.assertEqual(f([]), "default")
+ self.assertEqual(f(""), "types.UnionType") # last one wins
+ self.assertEqual(f(b""), "typing.Union")
+ self.assertEqual(f(1), "types.UnionType")
+
+ def test_union_None(self):
+ @functools.singledispatch
+ def typing_union(arg):
+ return "default"
+
+ @typing_union.register
+ def _(arg: typing.Union[str, None]):
+ return "typing.Union"
+
+ self.assertEqual(typing_union(1), "default")
+ self.assertEqual(typing_union(""), "typing.Union")
+ self.assertEqual(typing_union(None), "typing.Union")
+
+ @functools.singledispatch
+ def types_union(arg):
+ return "default"
+
+ @types_union.register
+ def _(arg: int | None):
+ return "types.UnionType"
+
+ self.assertEqual(types_union(""), "default")
+ self.assertEqual(types_union(1), "types.UnionType")
+ self.assertEqual(types_union(None), "types.UnionType")
+
def test_register_genericalias(self):
@functools.singledispatch
def f(arg):
