mobcode

Requirements, people, and monsters (part 4)

The final complex system is the application we build: the system. Over time the system becomes a monster. A monster that threatens the team by causing damage, demanding attention, creating more urgent work, growing out of control, refusing to cooperate, and generally causing pain for the development team. The source code grows into a monster. The running system grows into another kind of monster.

The task is to tame the beast. The monster is supposed to serve the team and the users, not the other way around. We need to get the beast in a cage, tame him, get a bit in his mouth, and steer him where we want. We must make the monster serve people.

Once again, the agile movement shows us many of the key techniques we need. Create automated unit tests around each piece of the system. Create automated end-to-end functional tests that confirm the whole thing works as expected. These tests create a cage that constrains the monster.

Build with an eye to creating visible workings. The system cannot be a black box, it has to show its users what it is doing. The system has to provide useful logging and monitoring. Now people can reason about its behavior rather than making up superstitions to explain the rampages of the beast.

With extensive tests in place the development team has a safety net that emboldens them to keep the design from deteriorating into a big ball of mud. When a coder is working on a piece of code and when they see how terrible the code is they can make it better and count on the tests to help them keep things working. The code base can be steered in the direction of good design. The monster has a bit in his mouth.

Software development projects are dominated by these three complex systems: the requirements, the team, and the application itself. Each one of these offers endless opportunities for learning. Any one of them can run out of control and cause misery. Welcome to the joyful world of software development.