Test what, our patience? Seriously, even if anyone here were inclined to simply provide code to you - which we are not - you would need to give a lot more detail about what you need.
One of the forum rules states that, when posting for help with a program, you must demonstrate due diligence - you need to show that you have made a good-faith effort to solve the problem yourself, and that you have reached an impasse you can't reslove. In other words, show us your code. If you don't have any code to show us, tell us what you need help in doing. Make an effort first, before asking for a hand-out.
Presumably the purpose is to show 'this is a "test"' as the output. Unfortunately, the code is wrong even if you exclude the syntax error in your return statement. You must escape double quotes in a string:
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...