bpo-40679: Use the function's qualname in certain TypeErrors (GH-20236)

Patch by Dennis Sweeney.

1 files changed, 48 insertions, 0 deletions

diff --git a/Lib/test/test_call.py b/Lib/test/test_call.py
index 451a717..3f45922 100644
--- a/Lib/test/test_call.py
+++ b/Lib/test/test_call.py
@@ -8,6 +8,7 @@ import struct
 import collections
 import itertools
 import gc
+import contextlib
 
 
 class FunctionCalls(unittest.TestCase):
@@ -665,5 +666,52 @@ class TestPEP590(unittest.TestCase):
                 self.assertEqual(expected, wrapped(*args, **kwargs))
 
 
+class A:
+    def method_two_args(self, x, y):
+        pass
+
+    @staticmethod
+    def static_no_args():
+        pass
+
+    @staticmethod
+    def positional_only(arg, /):
+        pass
+
+@cpython_only
+class TestErrorMessagesUseQualifiedName(unittest.TestCase):
+
+    @contextlib.contextmanager
+    def check_raises_type_error(self, message):
+        with self.assertRaises(TypeError) as cm:
+            yield
+        self.assertEqual(str(cm.exception), message)
+
+    def test_missing_arguments(self):
+        msg = "A.method_two_args() missing 1 required positional argument: 'y'"
+        with self.check_raises_type_error(msg):
+            A().method_two_args("x")
+
+    def test_too_many_positional(self):
+        msg = "A.static_no_args() takes 0 positional arguments but 1 was given"
+        with self.check_raises_type_error(msg):
+            A.static_no_args("oops it's an arg")
+
+    def test_positional_only_passed_as_keyword(self):
+        msg = "A.positional_only() got some positional-only arguments passed as keyword arguments: 'arg'"
+        with self.check_raises_type_error(msg):
+            A.positional_only(arg="x")
+
+    def test_unexpected_keyword(self):
+        msg = "A.method_two_args() got an unexpected keyword argument 'bad'"
+        with self.check_raises_type_error(msg):
+            A().method_two_args(bad="x")
+
+    def test_multiple_values(self):
+        msg = "A.method_two_args() got multiple values for argument 'x'"
+        with self.check_raises_type_error(msg):
+            A().method_two_args("x", "y", x="oops")
+
+
 if __name__ == "__main__":
     unittest.main()