code: def test_astype_noncontiguous(self, index_slice):
      # GH#42396
      data = np.arange(16).reshape(4, 4)
      df = DataFrame(data)
  
      result = df.iloc[index_slice].astype("int16")
      expected = df.iloc[index_slice]
      tm.assert_frame_equal(result, expected, check_dtype=False)
  
imports: import re
  import numpy
  import pytest
  import pandas.util._test_decorators
  import pandas
  from pandas import Categorical, CategoricalDtype, DataFrame, DatetimeTZDtype, Index, Interval, IntervalDtype, NaT, Series, Timedelta, Timestamp, concat, date_range, option_context
  import pandas._testing
label_desc: Use image node_id 39 for calling the TestAstype obj's underlying member method code with example usage: obj.test_astype_noncontiguous(index_slice) without return types