Oh, the Coder and the Tester can be Friends, can be Friends...

(with apologies to Oklahoma!)

Elisabeth Hendrickson just tweeted about a thought-provoking analysis by Michael Bolton of the much-vaunted Continuous Deployment at IMVU.

I'm a big fan of TDD, Automated Tests and Continuous Integration, but I'd hate to develop without help from good Testers. A couple of years ago I worked on a dream project; a very small, highly skilled team which included a couple of developers, a tester and a business analyst. We were pair-programming, and my pairs came from a pool that included some of the best agile developers in the UK. The Tester and Business Analyst were also outstanding.

Our defect rate was very low: five defects in UAT, none in production over a twelve-month period. There's no doubt that this was a team effort; the Tester and the BA both caught many defects that were caused by problems we developers hadn't though of, and therefore never tested for. Equally, the developers tested so thoroughly that the Tester and BA could focus on the hard stuff, where their skills contributed maximum value.

For reasons that need not concern us, the application initially went into production on a machine that was controlled by the developers. We could have done continuous deployment, but we didn't. We always asked our Tester to do a final check-through on our staging box; mostly he found nothing, but once or twice he found defects that would have been real embarrasments in production. Of course, that wasn't his only contribution; our acceptance tests were the product of very close collaboration by the whole team.

So it was no surprise to read to read about Michael Bolton's experience when he did some manual testing of the IMVU site. IMVU practise Continuous Deployment, and claim to rely entirely on Automated Tests. Read Bolton's 50 Deployments A Day and The Perpetual Beta and see the consequences.

Testing Hibernate-based Persistent objects without Spring

Nat Pryce just pointed me at an excellent article on Testing Persistent Objects Without Spring by James Richardson.

It shows both the integration test and the code under test.

Lots of good ideas/good practice.

Automated end-to-end testing made easier with VMWare Server

Automated testing is one of the most important practices in Agile Development. I like to have a hierarchy of automated tests that cover the whole system as deployed and all of its component parts, right down to unit tests that tell me whether each class is fulfilling its contract.


Starting with end-to-end tests

There's a lot published about unit testing and acceptance tests, but much less about end-to-end testing. That's disappointing, given that end-to-end tests are arguably the first thing you should work on when developing a new application.

The need for a clean deployment environment

End-to-end testing gives you a chance to check out your deployment process and verify that the deployed application works in the target environment. Sometimes, though, a badly planned testing process can lull you into a false sense of security; most of us have encountered applications that work well in their test environment but fail when deployed to a clean machine.

It usually takes too much time and effort to create a fresh testing environment from scratch every time you want to do an end-to-end test. There is a simple fast alternative using VMWare Server.

VMware server to the rescue

VMware server is a free (as in beer) version of VMware's virtualisation software. I run it on an Ubuntu server, and use it to create a clean environment for applications that I'm developing. It has a snapshot capability that allows me to capture a clean "before deployment" image, and restore that in a few seconds prior to running a test. Best of all, there's an external scripting interface which allows you to automate the process.

You can download VMware Server for free (after registration). I also use their commercial VMware workstation product; the two play well together, as you'd expect, but you can do everything you need for end-to-end testing with the free product.