TST(string dtype): Make str.decode return str dtype

Author: rhshadrach

pandas/core/strings/accessor.py

@@ -12,6 +12,8 @@
 
 import numpy as np
 
+from pandas._config import get_option
+
 from pandas._libs import lib
 from pandas._typing import (
     AlignJoin,
@@ -399,7 +401,9 @@ def cons_row(x):
             # This is a mess.
             _dtype: DtypeObj | str | None = dtype
             vdtype = getattr(result, "dtype", None)
-            if self._is_string:
+            if _dtype is not None:
+                pass
+            elif self._is_string:
                 if is_bool_dtype(vdtype):
                     _dtype = result.dtype
                 elif returns_string:
@@ -2140,9 +2144,9 @@ def decode(self, encoding, errors: str = "strict"):
             decoder = codecs.getdecoder(encoding)
             f = lambda x: decoder(x, errors)[0]
         arr = self._data.array
-        # assert isinstance(arr, (StringArray,))
         result = arr._str_map(f)
-        return self._wrap_result(result)
+        dtype = "str" if get_option("future.infer_string") else None
+        return self._wrap_result(result, dtype=dtype)
 
     @forbid_nonstring_types(["bytes"])
     def encode(self, encoding, errors: str = "strict"):

pandas/tests/io/sas/test_sas7bdat.py

@@ -7,8 +7,6 @@
 import numpy as np
 import pytest
 
-from pandas._config import using_string_dtype
-
 from pandas.compat._constants import (
     IS64,
     WASM,
@@ -20,10 +18,6 @@
 
 from pandas.io.sas.sas7bdat import SAS7BDATReader
 
-pytestmark = pytest.mark.xfail(
-    using_string_dtype(), reason="TODO(infer_string)", strict=False
-)
-
 
 @pytest.fixture
 def dirpath(datapath):

pandas/tests/strings/test_strings.py

@@ -566,7 +566,7 @@ def test_string_slice_out_of_bounds(any_string_dtype):
 def test_encode_decode(any_string_dtype):
     ser = Series(["a", "b", "a\xe4"], dtype=any_string_dtype).str.encode("utf-8")
     result = ser.str.decode("utf-8")
-    expected = ser.map(lambda x: x.decode("utf-8")).astype(object)
+    expected = Series(["a", "b", "a\xe4"], dtype="str")
     tm.assert_series_equal(result, expected)