gh-124665: Add `_PyCodec_UnregisterError` and `_codecs._unregister_error` (#124677)

1 files changed, 26 insertions, 1 deletions

diff --git a/Lib/test/test_codeccallbacks.py b/Lib/test/test_codeccallbacks.py
index 4991330..86e5e5c 100644
--- a/Lib/test/test_codeccallbacks.py
+++ b/Lib/test/test_codeccallbacks.py
@@ -1,3 +1,4 @@
+from _codecs import _unregister_error as _codecs_unregister_error
 import codecs
 import html.entities
 import itertools
@@ -1210,7 +1211,6 @@ class CodecCallbackTest(unittest.TestCase):
             '\ufffd\x00\x00'
         )
 
-
     def test_fake_error_class(self):
         handlers = [
             codecs.strict_errors,
@@ -1235,6 +1235,31 @@ class CodecCallbackTest(unittest.TestCase):
                     with self.assertRaises((TypeError, FakeUnicodeError)):
                         handler(FakeUnicodeError())
 
+    def test_reject_unregister_builtin_error_handler(self):
+        for name in [
+            'strict', 'ignore', 'replace', 'backslashreplace', 'namereplace',
+            'xmlcharrefreplace', 'surrogateescape', 'surrogatepass',
+        ]:
+            with self.subTest(name):
+                self.assertRaises(ValueError, _codecs_unregister_error, name)
+
+    def test_unregister_custom_error_handler(self):
+        def custom_handler(exc):
+            raise exc
+
+        custom_name = 'test.test_unregister_custom_error_handler'
+        self.assertRaises(LookupError, codecs.lookup_error, custom_name)
+        codecs.register_error(custom_name, custom_handler)
+        self.assertIs(codecs.lookup_error(custom_name), custom_handler)
+        self.assertTrue(_codecs_unregister_error(custom_name))
+        self.assertRaises(LookupError, codecs.lookup_error, custom_name)
+
+    def test_unregister_custom_unknown_error_handler(self):
+        unknown_name = 'test.test_unregister_custom_unknown_error_handler'
+        self.assertRaises(LookupError, codecs.lookup_error, unknown_name)
+        self.assertFalse(_codecs_unregister_error(unknown_name))
+        self.assertRaises(LookupError, codecs.lookup_error, unknown_name)
+
 
 if __name__ == "__main__":
     unittest.main()