public void ParseIfCommand()
{
ICommand command = ParseCommand("if (c<=1) return 1;");
Assert.IsNotNull(command);
Assert.IsInstanceOfType(command, typeof(IfCommand));
IfCommand ifcmd = (IfCommand)command;
Assert.IsNotNull(ifcmd.Condition);
Assert.IsNotNull(ifcmd.ThenCommand);
Assert.IsNull(ifcmd.ElseCommand);
}