Issue #26167: Backported copy tests.

Author: serhiy-storchaka

Lib/test/test_copy.py

@@ -95,24 +95,67 @@ def f():
             pass
         class WithMetaclass(metaclass=abc.ABCMeta):
             pass
-        tests = [None, 42, 2**100, 3.14, True, False, 1j,
+        tests = [None, ..., NotImplemented,
+                 42, 2**100, 3.14, True, False, 1j,
                  "hello", "hello\u1234", f.__code__,
-                 b"world", bytes(range(256)),
-                 NewStyle, range(10), Classic, max, WithMetaclass]
+                 b"world", bytes(range(256)), range(10),
+                 NewStyle, Classic, max, WithMetaclass]
         for x in tests:
             self.assertIs(copy.copy(x), x)
 
     def test_copy_list(self):
         x = [1, 2, 3]
-        self.assertEqual(copy.copy(x), x)
+        y = copy.copy(x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y, x)
+        x = []
+        y = copy.copy(x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y, x)
 
     def test_copy_tuple(self):
         x = (1, 2, 3)
-        self.assertEqual(copy.copy(x), x)
+        self.assertIs(copy.copy(x), x)
+        x = ()
+        self.assertIs(copy.copy(x), x)
+        x = (1, 2, 3, [])
+        self.assertIs(copy.copy(x), x)
 
     def test_copy_dict(self):
         x = {"foo": 1, "bar": 2}
-        self.assertEqual(copy.copy(x), x)
+        y = copy.copy(x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y, x)
+        x = {}
+        y = copy.copy(x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y, x)
+
+    def test_copy_set(self):
+        x = {1, 2, 3}
+        y = copy.copy(x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y, x)
+        x = set()
+        y = copy.copy(x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y, x)
+
+    def test_copy_frozenset(self):
+        x = frozenset({1, 2, 3})
+        self.assertIs(copy.copy(x), x)
+        x = frozenset()
+        self.assertIs(copy.copy(x), x)
+
+    def test_copy_bytearray(self):
+        x = bytearray(b'abc')
+        y = copy.copy(x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y, x)
+        x = bytearray()
+        y = copy.copy(x)
+        self.assertEqual(y, x)
+        self.assertIsNot(y, x)
 
     def test_copy_inst_vanilla(self):
         class C: