python · miss-islington · Aug 13, 2021 · Aug 13, 2021
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
@@ -1169,6 +1169,28 @@ class BufferBlocked(bytearray):
        self.assertEqual(bytes(ba), b'ab')
        self.assertRaises(TypeError, bytes, bb)

+    def test_repeat_id_preserving(self):
+        a = b'123abc1@'
+        b = b'456zyx-+'
+        self.assertEqual(id(a), id(a))
+        self.assertNotEqual(id(a), id(b))
+        self.assertNotEqual(id(a), id(a * -4))
+        self.assertNotEqual(id(a), id(a * 0))
+        self.assertEqual(id(a), id(a * 1))
+        self.assertEqual(id(a), id(1 * a))
+        self.assertNotEqual(id(a), id(a * 2))
+
+        class SubBytes(bytes):
+            pass
+
+        s = SubBytes(b'qwerty()')
+        self.assertEqual(id(s), id(s))
+        self.assertNotEqual(id(s), id(s * -4))
+        self.assertNotEqual(id(s), id(s * 0))
+        self.assertNotEqual(id(s), id(s * 1))
+        self.assertNotEqual(id(s), id(1 * s))
+        self.assertNotEqual(id(s), id(s * 2))
+

 class ByteArrayTest(BaseBytesTest, unittest.TestCase):
    type2test = bytearray

diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
@@ -508,6 +508,28 @@ def test_replace_id(self):
        text = 'abc def'
        self.assertIs(text.replace(pattern, pattern), text)

+    def test_repeat_id_preserving(self):
+        a = '123abc1@'
+        b = '456zyx-+'
+        self.assertEqual(id(a), id(a))
+        self.assertNotEqual(id(a), id(b))
+        self.assertNotEqual(id(a), id(a * -4))
+        self.assertNotEqual(id(a), id(a * 0))
+        self.assertEqual(id(a), id(a * 1))
+        self.assertEqual(id(a), id(1 * a))
+        self.assertNotEqual(id(a), id(a * 2))
+
+        class SubStr(str):
+            pass
+
+        s = SubStr('qwerty()')
+        self.assertEqual(id(s), id(s))
+        self.assertNotEqual(id(s), id(s * -4))
+        self.assertNotEqual(id(s), id(s * 0))
+        self.assertNotEqual(id(s), id(s * 1))
+        self.assertNotEqual(id(s), id(1 * s))
+        self.assertNotEqual(id(s), id(s * 2))
+
    def test_bytes_comparison(self):
        with warnings_helper.check_warnings():
            warnings.simplefilter('ignore', BytesWarning)

diff --git a/Misc/NEWS.d/next/Tests/2021-08-13-12-11-06.bpo-44891.T9_mBT.rst b/Misc/NEWS.d/next/Tests/2021-08-13-12-11-06.bpo-44891.T9_mBT.rst
@@ -0,0 +1,2 @@
+Tests were added to clarify :func:`id` is preserved when ``obj * 1`` is used
+on :class:`str` and :class:`bytes` objects. Patch by Nikita Sobolev.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Tests were added to clarify :func:`id` is preserved when ``obj * 1`` is used
		on :class:`str` and :class:`bytes` objects. Patch by Nikita Sobolev.