function testTree_TableAccess_CrossColumnIndex_Unaffected() {
  var treeBefore =
      'project()\n' +
      '-order_by(CrossColumnTable.string DESC, ' +
          'CrossColumnTable.number ASC)\n' +
      '--select(value_pred(CrossColumnTable.boolean eq false))\n' +
      '---table_access(CrossColumnTable)\n';

  lf.testing.treeutil.assertTreeTransformation(
      constructTree2(lf.Order.DESC, lf.Order.ASC),
      treeBefore, treeBefore, pass);
}
Tests the case where an existing cross-column index can't be leveraged to
perform the ORDER BY, even though it refers to the same columns as the ORDER
BY because the requested order does not match the index's natural or reverse
order.