This post is just a small remainder of the meta-physical questions I'm asking myself, specially because testing is basically trying to solve an unsolvable problem (Halting theorem)

1. What is a bug ? (I like this one)
2. Are there family of bugs ? (see Mutation Testing) Can we detect them statically (i.e. using Metadata only)
3. Is there a way to get an a-priori estimation on the location of the bugs ?
4. Can we apply Risk Managment technology to source code ? Automatically ?
5. How can you effectively test a database ? By effectively I mean: not restricted to transactions, not database reconstruction for each test,
6. How can you effectively test a GUI ? By effectively I mean, without having to actually record and program user interfaction,
7. Should you test the code that does the testing ? If yes, should you test the code that tests code that does the testing... and so on,
8. You are facing an untested application, you don't have the time to test all the code. Where should you start ?