Fix test_ne in test_cmp.py for Python 3.13

Compiler in Python 3.13+ strips indents from docstrings
so they need to be compared without it for new Pythons.

Fixes: #1228

src/attr/_compat.py

@@ -14,6 +14,7 @@
 PY_3_9_PLUS = sys.version_info[:2] >= (3, 9)
 PY310 = sys.version_info[:2] >= (3, 10)
 PY_3_12_PLUS = sys.version_info[:2] >= (3, 12)
+PY_3_13_PLUS = sys.version_info[:2] >= (3, 13)
 
 
 if sys.version_info < (3, 8):

tests/test_cmp.py

@@ -4,10 +4,10 @@
 Tests for methods from `attrib._cmp`.
 """
 
-
 import pytest
 
 from attr._cmp import cmp_using
+from attr._compat import PY_3_13_PLUS
 
 
 # Test parameters.
@@ -54,6 +54,9 @@
 cmp_data = eq_data + order_data
 cmp_ids = eq_ids + order_ids
 
+# Compiler strips indents from docstrings in Python 3.13+
+indent = "" if PY_3_13_PLUS else " " * 8
+
 
 class TestEqOrder:
     """
@@ -325,7 +328,7 @@ def test_ne(self):
         method = self.cls.__ne__
         assert method.__doc__.strip() == (
             "Check equality and either forward a NotImplemented or\n"
-            "        return the result negated."
+           f"{indent}return the result negated."
         )
         assert method.__name__ == "__ne__"
 
@@ -393,7 +396,7 @@ def test_ne(self):
         method = self.cls.__ne__
         assert method.__doc__.strip() == (
             "Check equality and either forward a NotImplemented or\n"
-            "        return the result negated."
+           f"{indent}return the result negated."
         )
         assert method.__name__ == "__ne__"
 
@@ -465,7 +468,7 @@ def test_ne(self):
         method = self.cls.__ne__
         assert method.__doc__.strip() == (
             "Check equality and either forward a NotImplemented or\n"
-            "        return the result negated."
+            f"{indent}return the result negated."
         )
         assert method.__name__ == "__ne__"