Apply suggestions from code review

Co-authored-by: Bruno Oliveira <[email protected]>

Author: Pierre-Sassoulas

src/_pytest/mark/structures.py

@@ -49,7 +49,7 @@ def get_empty_parameterset_mark(
 
     fs, lineno = getfslineno(func)
     reason = (
-        f"got empty parameter set {argnames}, function {func.__name__} at {fs}:{lineno}"
+        f"got empty parameter set {argnames!r}, function {func.__name__} at {fs}:{lineno}"
     )
     requested_mark = config.getini(EMPTY_PARAMETERSET_OPTION)
     if requested_mark in ("", None, "skip"):

testing/example_scripts/dataclasses/test_compare_dataclasses_with_custom_eq.py

@@ -10,8 +10,8 @@ class SimpleDataObject:
         field_a: int = field()
         field_b: str = field()
 
-        def __eq__(self, __o: object, /) -> bool:
-            return super().__eq__(__o)
+        def __eq__(self, o: object, /) -> bool:
+            return super().__eq__(o)
 
     left = SimpleDataObject(1, "b")
     right = SimpleDataObject(1, "c")