class_docstr: Casting to and from ExtensionDtypes
code: def test_astype_object_frame(self, all_data):
      df = pd.DataFrame({"A": all_data})
  
      result = df.astype(object)
      if hasattr(result._mgr, "blocks"):
          blk = result._mgr.blocks[0]
          assert isinstance(blk, NumpyBlock), type(blk)
          assert blk.is_object
      assert isinstance(result._mgr.arrays[0], np.ndarray)
      assert result._mgr.arrays[0].dtype == np.dtype(object)
  
      # check that we can compare the dtypes
      comp = result.dtypes == df.dtypes
      assert not comp.any()
  
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 2 for calling the BaseCastingTests obj's underlying member method code with example usage: obj.test_astype_object_frame(all_data) without return types