Fixed Index.rename() and added test

Author: devesh-2002

pandas-stubs/core/indexes/base.pyi

@@ -292,7 +292,7 @@ class Index(IndexOpsMixin[S1]):
     @names.setter
     def names(self, names: list[_str]): ...
     def set_names(self, names, *, level=..., inplace: bool = ...): ...
-    def rename(self, name, inplace: bool = ...): ...
+    def rename(self, name, inplace: bool = ...) -> Self: ...
     @property
     def nlevels(self) -> int: ...
     def sortlevel(self, level=..., ascending: bool = ..., sort_remaining=...): ...

tests/test_indexes.py

@@ -112,6 +112,11 @@ def test_str_split() -> None:
     check(assert_type(ind.str.split("-"), "pd.Index[str]"), pd.Index)
     check(assert_type(ind.str.split("-", expand=True), pd.MultiIndex), pd.MultiIndex)
 
+def test_index_rename() -> None:
+    ind = pd.Index([1, 2, 3], name="foo")
+    ind2 = ind.rename("goo")
+    check(assert_type(ind2, pd.Index), pd.Index)
+
 
 def test_index_dropna():
     idx = pd.Index([1, 2])