Continuous Integration

When I was a developer at a small company that sold products which happened to include software we did a lot of things different. The main reason for this is that software was a part of what we were producing, but not the main part. Elevators, electric dune buggies, CNC machines all have significant non-software development components.

The delta's show in how much attention is paid to the processes surrounding the development of each component. For example, one of our favourite ways to test software that was developed for CNC machines was to load the software onto a CNC machine and press buttons and use any new software that was implemented. The goal was to test the software for correctness and bugs. To us, this was a reasonable facsimile to a production environment.

I now work on a large team of software developers who are professionals at producing software. It's very time consuming or even impossible to test new software IRL because the production environment is not easily simulated. Continuous integration and unit testing allows me to develop software and be reasonably secure how it will perform in the field without having to 'press the buttons'.

Of course, running unit tests is not foreign to the previous shops in which I've practiced my craft. The problem with unit tests was almost always the same. The tests would be run during the development of a feature, then never used again. Instead, they might never see the inside of a version control system. They would be lost on next computer upgrade. It was hard to justify so much time writing unit tests that would only be used to aid the developer implement.

With Continuous Integration, it's different. The build and integrate process is continuous (imagine that). Each build is done on a dedicated system. All unit tests are automatically run and if everything goes ok, the build is deployed to testing fixtures which run continuously.

This process makes it more difficult for new code to break old code (as long as it's adequately tested). I wish I knew that before I wasted all those hours tracking down bugs by trying to manually set them up over and over with the user interface.