code: def test_astype_string_and_object(
      using_copy_on_write, dtype, new_dtype
  ):
      df = DataFrame({"a": ["a", "b", "c"]}, dtype=dtype)
      df_orig = df.copy()
      df2 = df.astype(new_dtype)
  
      if using_copy_on_write:
          assert np.shares_memory(
              get_array(df2, "a"), get_array(df, "a")
          )
      else:
          assert not np.shares_memory(
              get_array(df2, "a"), get_array(df, "a")
          )
  
      df2.iloc[0, 0] = "x"
      tm.assert_frame_equal(df, df_orig)
  
imports: import pickle
  import numpy
  import pytest
  from pandas.compat.pyarrow import pa_version_under12p0
  import pandas
  from pandas import DataFrame, Series, Timestamp, date_range
  import pandas._testing
  from pandas.tests.copy_view.util import get_array
label_desc: Use image node_id 5 for calling a global function with example usage: test_astype_string_and_object(using_copy_on_write, dtype, new_dtype) without return types