code: def test_where(self, listlike_box):
      klass = listlike_box
  
      i = CategoricalIndex(
          list("aabbca"), categories=list("cab"), ordered=False
      )
      cond = [True] * len(i)
      expected = i
      result = i.where(klass(cond))
      tm.assert_index_equal(result, expected)
  
      cond = [False] + [True] * (len(i) - 1)
      expected = CategoricalIndex(
          [np.nan] + i[1:].tolist(), categories=i.categories
      )
      result = i.where(klass(cond))
      tm.assert_index_equal(result, expected)
  
imports: import numpy
  import pytest
  from pandas.errors import InvalidIndexError
  import pandas
  from pandas import CategoricalIndex, Index, IntervalIndex, Timestamp
  import pandas._testing
label_desc: Use image node_id 1 for calling the TestWhere obj's underlying member method code with example usage: obj.test_where(listlike_box) without return types