Address review: fix comment style and move test

Author: pareshjoshij

Lib/email/_header_value_parser.py

@@ -2792,8 +2792,7 @@ def _steal_trailing_WSP_if_exists(lines):
     if lines and lines[-1] and lines[-1][-1] in WSP:
         wsp = lines[-1][-1]
         lines[-1] = lines[-1][:-1]
-        # FIX: If the line is now empty (it was only a space), remove it entirely
-        # to prevent creating an empty line (double newline) in the output.
+        # gh-142006: if the line is now empty, remove it entirely.
         if not lines[-1]:
             lines.pop()
     return wsp

Lib/test/test_email/test__header_value_parser.py

@@ -3255,5 +3255,18 @@ def test_long_filename_attachment(self):
             " filename*1*=_TEST_TES.txt\n",
             )
 
+    def test_fold_unfoldable_element_stealing_whitespace(self):
+        # gh-142006: When an element is too long to fit on the current line
+        # the previous line's trailing whitespace
+        policy = self.policy.clone(max_line_length=10)
+
+        # "a," fits. The space after it should wrap to the next line.
+        # The "long" part (20 chars) forces the wrap because 20 > 10.
+        text = "a, " + ("b" * 20)
+        expected = "a,\n " + ("b" * 20) + "\n"
+
+        token = parser.get_address_list(text)[0]
+        self._test(token, expected, policy=policy)
+
 if __name__ == '__main__':
     unittest.main()

Lib/test/test_email/test_policy.py

@@ -165,20 +165,6 @@ def test_fold_zero_max_line_length(self):
         self.assertEqual(p1.fold('Subject', msg['Subject']), expected)
         self.assertEqual(p2.fold('Subject', msg['Subject']), expected)
 
-    def test_fold_address_list_with_stolen_whitespace(self):
-        long_address = (
-            "loooooooooooooooooooooooooooooooooooong@dooooooooooooomainname.example.com, "
-            "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.example.com"
-        )
-        msg = email.message_from_string(f"To: {long_address}\n\n", policy=email.policy.default)
-
-        # This should not raise HeaderWriteError
-        output = msg.as_string()
-        # Verify the output format is correct and clean
-        self.assertIn(long_address.split(',')[0], output)
-        # Ensure header section doesn't have double newlines
-        self.assertNotIn('\n\n', output.split('\n\n')[0])
-
     def test_register_defect(self):
         class Dummy:
             def __init__(self):