class_docstr: Casting to and from ExtensionDtypes
code: def test_astype_own_type(self, data, copy):
      # ensure that astype returns the original object for equal dtype and copy=False
      # https://github.com/pandas-dev/pandas/issues/28488
      result = data.astype(data.dtype, copy=copy)
      assert (result is data) is (not copy)
      tm.assert_extension_array_equal(result, data)
  
file_path: pandas/pandas/tests/extension/base/casting.py
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  import pandas
  import pandas._testing
  from pandas.core.internals.blocks import NumpyBlock
label_desc: Use image node_id 8 for calling the BaseCastingTests obj's underlying member method code with example usage: obj.test_astype_own_type(data, copy) without return types