function test_IsNull_Indexed() {
  var tableSchema = db.getSchema().getRegion();
  // Ensure that the 'id' field is indexed.
  assertTrue(tableSchema.id.getIndices().length >= 1);

  /**
   * Select records to the database.
   * @return {!IThenable}
   */
  var selectFn = function() {
    return db.
        select().
        from(tableSchema).
        where(tableSchema.id.isNull()).
        exec();
  };

  return selectFn().then(
      function(result) {
        assertEquals(0, result.length);
      });
}
Tests the case where an isNull() predicate is used on an indexed field.
@return {!IThenable}