In general, when I have an issue, I try to produce a small snippet of code that shows the problem. I haven't done it as a unit test before, but I don't think I've ever submitted a bug report to a project that has them...<p>It helps both me and the developer, because the developer can run the code and see if he fixed -my- problem, rather than -a- problem, and I can run it afterwards to verify that it's fixed. I've also had it show that the same code will hit many bugs before it works... This allows the developer to fix it all the way down.