Like most people I have a few projects on the go at once. To efficiently switch between them I must be able to quickly pick up where I left off. In my programming projects I’ve been using failing tests as reminders to myself. This fits in nicely with my programming workflow, and enables me to make progress before I’ve recalled all the details of the project I’m working on. Here’s how it works:

In my programming workflow I cycle between writing tests, writing code, and running tests (this is just test driven development). When I’m about to stop working on a project I write some failing tests, which act as a specification for what I should do next. At this point in time I’ve been working on the project for a while so I have recalled its structure and I’m in a good position to make this decision.

When I pick up a project after a break I enter straight into my normal workflow and run my tests. I inspect the failing tests and start implementing the functionality they specify. At this point in time I don’t even have to remember why I’m implementing this; the tests provide enough detail that I can just start coding. As I do so I invariably recall more details of the project. By the time I’ve finished the feature I’m ready to go at full speed.

This technique allows me to “hide” the time it takes to recall the project details; I still get useful work done in this period. It’s quite a simple idea and no doubt some of you are already using it, but if you haven’t tried it, give it a shot.