code: def test_to_block_index(self, cases, test_length):
      xloc, xlen, yloc, ylen, _, _ = cases
      xindex = BlockIndex(test_length, xloc, xlen)
      yindex = BlockIndex(test_length, yloc, ylen)
  
      # see if survive the round trip
      xbindex = xindex.to_int_index().to_block_index()
      ybindex = yindex.to_int_index().to_block_index()
      assert isinstance(xbindex, BlockIndex)
      assert xbindex.equals(xindex)
      assert ybindex.equals(yindex)
  
imports: import operator
  import numpy
  import pytest
  import pandas._libs.sparse
  import pandas.util._test_decorators
  from pandas import Series
  import pandas._testing
  from pandas.core.arrays.sparse import BlockIndex, IntIndex, make_sparse_index
label_desc: Use image node_id 4 for calling the TestIntIndex obj's underlying member method code with example usage: obj.test_to_block_index(cases, test_length) without return types