One of the electric windows in my car failed last week. See my other blog for the whole sorry story. Anyhoo, I'm pretty sure that I've fixed it, in that every time I've used it since the repair it has worked.

However, this does not prove that the window is properly mended, only that it passed the most recent test. This points to a fundamental problem with testing; namely that it only ever proves the existence of problems, not that they aren't there. The rest you have to take on faith I suppose. This kind of means that at the end of the day the process by which you build your software should leave you with enough faith that it will work. Tests are good, but at the end of the day you need to believe in what you make as well.