TST (string-dtype): Adjust indexes string tests

Author: phofl

pandas/core/config_init.py

@@ -873,7 +873,7 @@ def register_converter_cb(key: str) -> None:
 with cf.config_prefix("future"):
     cf.register_option(
         "infer_string",
-        True,
+        True if os.environ.get("PANDAS_FUTURE_INFER_STRING", "0") == "1" else False,
         "Whether to infer sequence of str objects as pyarrow string "
         "dtype, which will be the default in pandas 3.0 "
         "(at which point this option will be deprecated).",