code: def test_astype_string_to_extension_dtype_roundtrip(
      self, data, dtype, request, nullable_string_dtype
  ):
      if dtype == "boolean":
          mark = pytest.mark.xfail(
              reason="TODO StringArray.astype() with missing values #GH40566"
          )
          request.applymarker(mark)
      # GH-40351
      ser = Series(data, dtype=dtype)
  
      # Note: just passing .astype(dtype) fails for dtype="category"
      #  with bc ser.dtype.categories will be object dtype whereas
      #  result.dtype.categories will have string dtype
      result = ser.astype(nullable_string_dtype).astype(ser.dtype)
      tm.assert_series_equal(result, ser)
  
imports: from datetime import datetime, timedelta
  from importlib import reload
  import string
  import sys
  import numpy
  import pytest
  from pandas._libs.tslibs import iNaT
  import pandas.util._test_decorators
  from pandas import NA, Categorical, CategoricalDtype, DatetimeTZDtype, Index, Interval, NaT, Series, Timedelta, Timestamp, cut, date_range, to_datetime
  import pandas._testing
label_desc: Use image node_id 1 for calling the TestAstypeString obj's underlying member method code with example usage: obj.test_astype_string_to_extension_dtype_roundtrip(data, dtype, request, nullable_string_dtype) without return types