As much as I love how easy it is to create a project on top of WordPress and release it into one of the free repositories, there are certain aspects of development that are neglected.
Case in point: testing.
And though I’ve been talking a little bit about unit testing, there are also other types of testing such as acceptance testing, integration testing, black-box testing, and so on.

This is not the type of black-box I had in mind.
All of the above are ways that we can go about ensuring a high degree of quality is built into our projects. Sometimes, I think we forgo these things for the sake of shipping something more quickly.
Other times, I think that we neglect to do them because writing tests is not as much fun as actually building a project. In other cases, I think that we opt not to test because we don’t have the proper education around the tooling for how to do so.
Don’t get me wrong: I have a much better track record of writing tests around client projects that I do about some of my public plugins (save for Easier Excerpts and Scheduled Post Shortcut which are done by Eric and myself), so I’m working to change that.
But if you don’t do any other type of testing, I urge you to at least try to introduce black-box testing into your development process.