text: import numpy as np
  
  import pandas as pd
  from pandas.core.internals import ObjectBlock
  
  from .base import BaseExtensionTests
  
  
  class BaseCastingTests(BaseExtensionTests):
      """Casting to and from ExtensionDtypes"""
  
      def test_astype_object_series(self, all_data):
          ser = pd.Series(all_data, name="A")
          result = ser.astype(object)
          assert isinstance(result._mgr.blocks[0], ObjectBlock)
  
      def test_astype_object_frame(self, all_data):
          df = pd.DataFrame({"A": all_data})
  
          result = df.astype(object)
          blk = result._data.blocks[0]
          assert isinstance(blk, ObjectBlock), type(blk)
  
          # FIXME: these currently fail; dont leave commented-out
          # check that we can compare the dtypes
          # cmp = result.dtypes.equals(df.dtypes)
          # assert not cmp.any()
  
      def test_tolist(self, data):
          result = pd.Series(data).tolist()
          expected = list(data)
          assert result == expected
  
      def test_astype_str(self, data):
          result = pd.Series(data[:5]).astype(str)
          expected = pd.Series([str(x) for x in data[:5]], dtype=str)
          self.assert_series_equal(result, expected)
  
      def test_astype_string(self, data):
          # GH-33465
          result = pd.Series(data[:5]).astype("string")
          expected = pd.Series([str(x) for x in data[:5]], dtype="string")
          self.assert_series_equal(result, expected)
  
      def test_to_numpy(self, data):
          expected = np.asarray(data)
  
          result = data.to_numpy()
          self.assert_equal(result, expected)
  
          result = pd.Series(data).to_numpy()
          self.assert_equal(result, expected)
  