Issue #27007: The fromhex() class methods of bytes and bytearray subclasses

now return an instance of corresponding subclass.

Lib/test/test_bytes.py

@@ -1589,7 +1589,32 @@ class SubclassTest:
             self.assertEqual(type(a), type(b))
             self.assertEqual(type(a.y), type(b.y))
 
-    test_fromhex = BaseBytesTest.test_fromhex
+    def test_fromhex(self):
+        b = self.type2test.fromhex('1a2B30')
+        self.assertEqual(b, b'\x1a\x2b\x30')
+        self.assertIs(type(b), self.type2test)
+
+        class B1(self.basetype):
+            def __new__(cls, value):
+                me = self.basetype.__new__(cls, value)
+                me.foo = 'bar'
+                return me
+
+        b = B1.fromhex('1a2B30')
+        self.assertEqual(b, b'\x1a\x2b\x30')
+        self.assertIs(type(b), B1)
+        self.assertEqual(b.foo, 'bar')
+
+        class B2(self.basetype):
+            def __init__(me, *args, **kwargs):
+                if self.basetype is not bytes:
+                    self.basetype.__init__(me, *args, **kwargs)
+                me.foo = 'bar'
+
+        b = B2.fromhex('1a2B30')
+        self.assertEqual(b, b'\x1a\x2b\x30')
+        self.assertIs(type(b), B2)
+        self.assertEqual(b.foo, 'bar')
 
 
 class ByteArraySubclass(bytearray):