code: def test_string_cancast(self, other_DT, string_char):
      fact = 1 if string_char == "S" else 4
  
      string_DT = type(np.dtype(string_char))
      cast = get_castingimpl(other_DT, string_DT)
  
      other_dt = other_DT()
      expected_length = get_expected_stringlength(other_dt)
      string_dt = np.dtype(f"{string_char}{expected_length}")
  
      (
          safety,
          (res_other_dt, res_dt),
          view_off,
      ) = cast._resolve_descriptors((other_dt, None))
      assert res_dt.itemsize == expected_length * fact
      assert (
          safety == Casting.safe
      )  # we consider to string casts "safe"
      assert view_off is None
      assert isinstance(res_dt, string_DT)
  
      # These casts currently implement changing the string length, so
      # check the cast-safety for too long/fixed string lengths:
      for change_length in [-1, 0, 1]:
          if change_length >= 0:
              expected_safety = Casting.safe
          else:
              expected_safety = Casting.same_kind
  
          to_dt = self.string_with_modified_length(
              string_dt, change_length
          )
          safety, (_, res_dt), view_off = cast._resolve_descriptors(
              (other_dt, to_dt)
          )
          assert res_dt is to_dt
          assert safety == expected_safety
          assert view_off is None
  
      # The opposite direction is always considered unsafe:
      cast = get_castingimpl(string_DT, other_DT)
  
      safety, _, view_off = cast._resolve_descriptors(
          (string_dt, other_dt)
      )
      assert safety == Casting.unsafe
      assert view_off is None
  
      cast = get_castingimpl(string_DT, other_DT)
      safety, (_, res_dt), view_off = cast._resolve_descriptors(
          (string_dt, None)
      )
      assert safety == Casting.unsafe
      assert view_off is None
      assert other_dt is res_dt
  
imports: import pytest
  import textwrap
  import enum
  import random
  import ctypes
  import numpy
  from numpy.lib.stride_tricks import as_strided
  from numpy.testing import assert_array_equal
  from numpy.core._multiarray_umath import _get_castingimpl
label_desc: Use image node_id 8 for calling the TestCasting obj's underlying member method code with example usage: obj.test_string_cancast(other_DT, string_char) without return types