code: def test_astype_generic_timestamp_no_frequency(self, dtype, request):
      # see GH#15524, GH#15987
      data = [1]
      ser = Series(data)
  
      if np.dtype(dtype).name not in ["timedelta64", "datetime64"]:
          mark = pytest.mark.xfail(
              reason="GH#33890 Is assigned ns unit"
          )
          request.applymarker(mark)
  
      msg = (
          rf"The '{dtype.__name__}' dtype has no unit\. "
          rf"Please pass in '{dtype.__name__}\[ns\]' instead."
      )
      with pytest.raises(ValueError, match=msg):
          ser.astype(dtype)
  
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 7 for calling the TestAstype obj's underlying member method code with example usage: obj.test_astype_generic_timestamp_no_frequency(dtype, request) without return types