public void Add()
{
IOrderByClause clause = new OrderByClause("field1 desc, field2");
var item = new OrderByItem("field3", SortOrder.Descending);
clause.Add(item);
Assert.AreEqual("field1 desc,field2,field3 desc", clause.ToString());
// can't add existing field
Assert.Throws <ArgumentException>(() =>
{
clause.Add("field2");
});
clause.AddAlways("field1", SortOrder.Ascending);
Assert.AreEqual("field2,field3 desc,field1", clause.ToString());
item.Reverse();
Assert.AreEqual("field2,field3,field1", clause.ToString());
}