FxCopy has nothing to do with any kind of testing, not in the sense you are talking about. FxCopy only helps to improve code quality without any direct concern of its functionality. For example, it helps to find unused references, excessive use of non-static (instance) methods, other performance flaws, even the violations of naming conventions. Put it in this way: it your fully take into account all the flaws detected by FxCop, the functionality of the code will remain exactly the same
. Do you see now that it is totally unrelated to what you want?
You have been confused. For final unconfusion, please read about penetration testing
So, what to Google for? Captain Obvious tells you: for "penetration test" or "testing". This is the most narrow query I could come up with: http://bit.ly/XnqVqL
Still, over 20 millions search results; and those I can see are quite relevant. Enough?
And no, this topic is totally unrelated to the notion "Click Once". You should not link one to another, otherwise it will lead you nowhere. Look for some penetration test and other test facilities and make sure they are suitable for .NET, your application-specific settings, requirements and testing criteria. And then it will suite your application, regardless of its deployment.