>The assertion has been made that typical applications have between 40%-50% of their code actually run during testing.
>
>I am curious to see what percentage of code you test (actually run during development/unit test/system testing) for:

>1) The development of a system from scratch.

Since I am doing in-house development, when we built our new system we ran parallel to the existing for several months and worked out interface issues and business rules. Than we launched after being satisfied that the data was safe and the bugs that only a user would find were left.

>2) The development of a new/replacement system but using code parts (including classes, functions, etc.) from existing and well-running systems.

The sytem we built took computations and data structure from the existing sytem, but extended its' capabiilties.

>3) Developing revisions to an existing application.

These are deployed to the people most likely to need the revision/addition for design and functionality feedback and then deployed to the people who are most likely to break it.

We strive to run 90+% of our code before releasing the application. Maybe only 50% or so in the IDE, and then I build a runtime version to really start having fun.

>Thanks for your reply.