function testGroupBy_ThrowsAlreadyCalled() {
  var query = new lf.query.SelectBuilder(hr.db.getGlobal(), []);

  var buildQuery = function() {
    var employeeTable = db.getSchema().getEmployee();
    query.from(employeeTable).
        groupBy(employeeTable.id).
        groupBy(employeeTable.jobId);
  };

  // 530: groupBy() has already been called.
  lf.testing.util.assertThrowsError(530, buildQuery);
}
Tests that Select#groupBy() fails if groupBy() has already been called.