I recently found out that Nester has been released. It's a C# port of Jester (one of my first open source projects).
Jester is a mutation testing tool. It tests test quality by seeing if mutations to your source code cause tests to fail or not. If no tests fail as a result of changing some code then that code might not be tested. It's different to code coverage. All code coverage can tell you is whether your code is executed by the tests; it says nothing about the quality of the tests. You could write tests with no assertions that had a 100% code coverage measure.
I'm thrilled that someone has done this port; I feel it's a milestone for any open source project that someone ports it.
There are lots of code coverage tools but very few mutation testing tools. I'm not entirely sure why this is. Jester is pretty difficult to use, slow to run and the results aren't always very easy to interpret, but apart from that ...
Posted by ivan at June 17, 2004 4:19 PMYou say that jester is difficult to use. Have you tried using Nester to see if it is any easier to use or have you tried speaking to others that have used both?
Boing boing
I haven't tried to use Nester myself, but as it is a port of Jester rather than a re-write I don't imagine it will be any easier to use. I might have been being slightly hard on Jester - it's not so difficult to use if you really do RTFM. I think the worst feature of getting Jester to work is that it isn't always clear at telling you why it isn't working, i.e. if you don't RTFM and try to get it to work by doing things that you think should make it work, you're likely to get very frustrated.
Posted by: ivan at August 12, 2004 4:42 PM