Sunday, December 26, 2010

Maven Surefire 2.7.1

Todays release of surefire 2.7.1 is an important milestone for me. Lets start out with what the 2.7 series has to offer

  • Multiple run-orders for tests now supported
    The runOrder attribute lets you specify alphabetical, reversealphabetical, random, hourly (alphabetical on even hours, reverse alphabetical on odd hours) and filesystem. Odd/Even for hourly is determined at the time the of scanning the classpath, meaning it could change during a multi-module build.
  • Faster, smaller
    About 1/3 of the total download size of 2.6. I get quite a lot of feedback saying it's significantly faster too; your mileage will vary.
  • Parallel JUnit
    Surefire is now totally self-contained and no longer uses ConfigurableParallelComputer for anything. Real execution times per test are also reported. It won't get much better than this.
  • Severe memory/resource leak fixed for those of you who have console output.
    The more your tests were writing to stdout/stderr, the worse the problem was. This one has been here since 2.4 ;)
  • Pluggable/Selectable providers
    Surefire is a framework for forking and reporting with a few additional features, such as directory scanning services. Until 2.7, this has all been wired together in one monolithic slab of code with test-providers ( TestNG, junit3/4/4.7) seemingly independent but in reality all welded together by massive dependencies and strange divisions of labor. No more. 2.7.X makes it possible to write your own providers. Best of all there's really not much work you need to do to create one.
    Need a "fork every 20 tests" provider? Fork one of the existing ones and make it yourself on github, probably in less than an hour. This also means we will be closing some of the more exotic requests as won't fix, since you can just do it yourself.
    Read about it here and here for the api
  • JDK 1.3 fork-compatibility restored.
    I ended up doing this just for the sheer heck of it; kind of a challenge. Pardon the language.

There's other issues fixed too, but these are the highlights.

* Why ?
I started programming on my C64 when I was 13 and I've been coding passionately ever since. I went to university and when I finished developing software became my day job. And although I keep my code clean, professional software development is also a lot about making deliveries with trade-offs and sometimes compromises. And we move on. If it doesn't come back to haunt us, it was probably good enough - no matter how frustrated you felt when making it.

Not so with my Open Source work. There I will only do stuff that somehow is the most excellent work I am capable of. It's the hobbyist computing returned, but my capacity is oh so infinitely different from when I was a teenager. Several OSS companies have offered me jobs, which I have turned down. If I was to take that I somehow feel I'd be taking the hobby as work once more.

So how does all of this relate to surefire? Until recently, surefire has been real messy code. While the basic design contains some interesting and pretty sophisticated stuff, it was basically a big mess. Huge classes with 400 line long methods is the trending topic. It was code without any discernible shape or form; mutable state mutating at every opportunity. All this mostly due to different people working on it at different points in time.

I've seen this happen, even with the best of people working together, and I will not dwell further as to the reasons for this. But I love working with the structure of code, and I think programming is communication; me talking to you - disconnected in time and space.

So I refactor. And I think. Sometimes I can think about a change for a week, code it in few hours only to realize it was wrong and throw it all away. Sometimes I can discover midway that there is a more important angle on solving the problem; something totally different is more important and will have bigger impact on future change. And I just stash away everything and do The Thing I Now Know Is Right. Repeat until satisifed.

I spent months of spare time working with surefire 2.7 this way. I think the results are pretty amazing; the plugin is basically transformed into clean code. Every year around Christmas time, I tend to bring this book to the fireplace. It's still one of the most amazing books written about how to think code. Kent has rewritten this book for Java several times, but I still recommend the Smalltalk version - even if you never programmed smalltalk. And take a look at surefire trunk. There's still work to do. Make a patch. Merry xmas.


  1. Kudos! Looking forward to put the new version into place when I'm back at work next week/year.

    Really liked your "Why" section too. Very inspiring to get my finger out and try to fix some "open sores" ;)

  2. Thanks, Thomas ! If nothing else, there's still lots of things to clean up in surefire. Whenever you clean *something* up, something else starts looking shoddy. Like painting only a few walls in your house.

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