assert result in test

Author: MarcoGorelli

pandas/core/frame.py

@@ -5352,7 +5352,7 @@ def shift(
             periods=periods, freq=freq, axis=axis, fill_value=fill_value
         )
 
-    @deprecate_nonkeyword_arguments(version="2.0", allowed_args=["self", "keys"])
+    @deprecate_nonkeyword_arguments(version=None, allowed_args=["self", "keys"])
     def set_index(
         self,
         keys,

pandas/tests/frame/methods/test_set_index.py

@@ -709,8 +709,10 @@ def test_drop_pos_args_deprecation(self):
         # https://github.com/pandas-dev/pandas/issues/41485
         df = DataFrame({"a": [1, 2, 3]})
         msg = (
-            r"Starting with Pandas version 2\.0 all arguments of set_index except for "
-            r"the arguments 'self' and 'keys' will be keyword-only"
+            r"In a future version of pandas all arguments of DataFrame\.set_index "
+            r"except for the argument 'keys' will be keyword-only"
         )
         with tm.assert_produces_warning(FutureWarning, match=msg):
-            df.set_index("a", True)
+            result = df.set_index("a", True)
+        expected = DataFrame(index=Index([1, 2, 3], name="a"))
+        tm.assert_frame_equal(result, expected)