I pointed out to someone at work today that PyDev 2.5.0 now offers really cool TDD support. I’m not a huge TDD proponent or anything, but this stirred up a discussion. This guy, let’s call him John, said that â€œTDD may shorten the time it takes to develop a feature, but sometimes a feature is so urgent we may want to deliver it as quickly as possible and test it later”.Sentences like that make me weep.I tried to explain that without testing, the risk of releasing a piece of code is unimaginable. As important as a feature may be, the product might be...

When developers first discover the wonders of test-driven development, it’s like gaining entrance to a new and better world with less stress and insecurity. It truly is a wonderful experience well worth celebrating. But internalizing the benefits of testing is only the first step to enlightenment. Knowing what not to test is the harder part of the lesson. While as a beginner you shouldn’t worry much about what not to test on day one, you better start picking it up by day two. Humans are creatures of habit, and if you start forming bad habits of over-testing early on, it will be h...

We do several kinds of testing. Some specifics:For our PHP code, we have a suite of a few thousand test classes using the PHPUnit framework. They range in complexity from simple true unit tests to large-scale integration tests that hit our production backend services. The PHPUnit tests are run both by developers as part of their workflow and continuously by an automated test runner on dedicated hardware. Our developer tools automatically use code coverage data to run tests that cover the outstanding edits in a developer sandbox, and a report of test results is automatically included in our cod...

This is an email I sent today to developers who work with me, it is exactly as I wrote it except for project and developer names which I’ve redacted.Dear Developers,S asked me a difficult question today, and I think the answer (which took me a few minutes to arrive at) is worth sharing with all developers, mainly because many of you will surely face the exact same problem especially in [maintenance and enhancement] projects.By now I think it is crystal clear that one of our non-negotiable requirements for coding is that we write unit tests.For new projects it is easy – in fact fo...

Over the years, I’ve come to hold some strong. opinions on testing, testers and the entire business of quality assurance. Inspired by this post on Facebook’s testing, I wanted to write this down so I can point people to it. Some of this is controversial. In fact, even mentioning some of this in conversation has caused people to flip the bozo bit on me.Most product teams don’t need a separate testing role. And even if they do, the ratio of full time dev:full time test should be in the order of >20:1. For evidence, look no further than some of the most successful engineer...