unit testing; interface uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls,mixercontroler,mmsystem; type TForm1 = class(TForm) Button1: TButton; procedure Button1Click(Sender: TObject); procedure FormActivate(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; a,b,c : TMixerKnob; d : TMixerPotWatcher; implementation {$R *.DFM} procedure TForm1.Button1Click(Sender: TObject); var v,t,bs : TKnobChanged; begin a:=TMixerKnob.create(form1); a.top:=100; a.left:=100; a.width:=40; a.height:=41; a.init(0); b:=TMixerKnob.create(form1); b.top:=200; b.left:=200; b.width:=40; b.height:=41; b.init(1); c:=TMixerKnob.create(form1); c.top:=200; c.left:=300; c.width:=40; c.height:=41; c.init(2); v:=a.PotChanged; t:=b.PotChanged; bs:=c.PotChanged; d:=TMixerPotWatcher.create(form1); d.init(v,t,bs); end; procedure TForm1.FormActivate(Sender: TObject); begin button1click(nil); end; end.