code: def test_astype(self, dtype):
      ser = Series(
          np.random.default_rng(2).standard_normal(5), name="foo"
      )
      as_typed = ser.astype(dtype)
  
      assert as_typed.dtype == dtype
      assert as_typed.name == ser.name
  
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 19 for calling the TestAstype obj's underlying member method code with example usage: obj.test_astype(dtype) without return types