code: def test_len_specialised(self, step):
      # make sure that our len is the same as np.arange calc
      start, stop = (0, 5) if step > 0 else (5, 0)
  
      arr = np.arange(start, stop, step)
      index = RangeIndex(start, stop, step)
      assert len(index) == len(arr)
  
      index = RangeIndex(stop, start, step)
      assert len(index) == 0
  
imports: import numpy
  import pytest
  from pandas.core.dtypes.common import ensure_platform_int
  import pandas
  from pandas import Index, RangeIndex
  import pandas._testing
label_desc: Use image node_id 35 for calling the TestRangeIndex obj's underlying member method code with example usage: obj.test_len_specialised(step) without return types