function testExec_ThrowsGroupByNonIndexableColumn() {
  var e = db.getSchema().getEmployee();
  var query = new lf.query.SelectBuilder(
      hr.db.getGlobal(), [e.email, e.salary, e.photo]);
  return lf.testing.util.assertPromiseReject(
      525,  // 525: Invalid projection list or groupBy columns.
      query.from(e).groupBy(e.photo).exec());
}
Tests that groupBy on non-indexable fields will fail.
@return {!IThenable}