1 files changed, 19 insertions, 0 deletions
diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index 5e741153f4..382ca03e5a 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -48,6 +48,7 @@ class TypesTests(unittest.TestCase):
     def test_float_constructor(self):
         self.assertRaises(ValueError, float, '')
         self.assertRaises(ValueError, float, '5\0')
+        self.assertRaises(ValueError, float, '5_5\0')
 
     def test_zero_division(self):
         try: 5.0 / 0.0
@@ -1000,6 +1001,24 @@ class ClassCreationTests(unittest.TestCase):
         with self.assertRaises(TypeError):
             X = types.new_class("X", (int(), C))
 
+    def test_one_argument_type(self):
+        expected_message = 'type.__new__() takes exactly 3 arguments (1 given)'
+
+        # Only type itself can use the one-argument form (#27157)
+        self.assertIs(type(5), int)
+
+        class M(type):
+            pass
+        with self.assertRaises(TypeError) as cm:
+            M(5)
+        self.assertEqual(str(cm.exception), expected_message)
+
+        class N(type, metaclass=M):
+            pass
+        with self.assertRaises(TypeError) as cm:
+            N(5)
+        self.assertEqual(str(cm.exception), expected_message)
+
 
 class SimpleNamespaceTests(unittest.TestCase):