When I went through a coding bootcamp, we only covered testing very briefly. We went over it as part of the lesson one day, were required to use it in one or two homework assignments, and then after that we never spoke much about it again and using it on any project was always optional.

From what I’ve seen, my experience was fairly typical. While most training programs for junior developers cover testing, very few go in depth or require TDD as a part of their workflow throughout the course. I understand the urge to not focus on it by teachers. It’s just another thing for students to learn in a schedule that’s already jam packed, and it’s a tool that not every company uses.

I however think TDD is one of the most effective ways to teach new programmers some of the most important parts of the trade. Two of the biggest benefits are learning to break down problems into small, manageable chunks and learning to decipher error messages effectively.

Breaking down the problem

By far the most common thing I see cripple new developers when they go to work on a project is simply being overwhelmed. They have a whole series of technical problems in front of them and knowing what to tackle at any one moment is difficult. This usually results in a jumbled code base where they have started several different tasks but not fully completed anything. I see this happen constantly. A student will ask me for help and I find that they have the setup for four different user flows but not one flow that a user could go all the way through successfully.

Writing tests, especially with an “outside-in” method where you focus on writing feature tests for what the user will be experiencing, forces junior developers to focus their efforts. It creates a strict set of guidelines. You can’t move on to anything else until the test you have in front of you is green.

Additionally, once they’ve gotten used to it in can really help to break down a problem. You start by thinking of what you expect to happen when a user goes through a scenario, and then you can work backwards to figure out what steps you need to make that happen. It serves the same purpose as writing an outline before you start on a paper.

Deciphering error messages

The second reason that I think testing is extremely helpful is that it forces you to learn to decipher error messages. Obviously, with or without tests junior developers are going to see a lot of error messages and exceptions. Typically, new programmers struggle a lot with these. Often they don’t read them at all. Seeing that they’ve gotten an error, they immediately go back to the last line of code they wrote and start playing with it to see if they can get the error to go away. They are intimidated by the wall of text that comes with an error and don’t know how to siphon out the important bits.

Without tests, users are typically working in the browser. They see the rails exceptions when there is a large problem but they don’t get the practice on more mundane things. With tests, if you have a typo in your text your test will fail. These small errors can be a big help in learning the important things to pay attention to, like line number, when deciphering an error message and can give much more practice than when you’re just seeing occasional exceptions in the browser.

There are other benefits I see from learning testing too. Like, for example, most other junior developers just aren’t as familiar with TDD, so learning it yourself can give you a competitive advantage in the job search and show that you care about your code quality. Additionally, junior developers should ideally be looking for companies that test their code thoroughly, since that provides juniors a safety net when they’re joining and nervous about making their first changes to production code. Having experience with testing will help attract these types of high quality companies

Many people think testing is too advanced for junior developers. I however think it was essential to my own development and one of the things that helped me learn at a quicker pace than some of my peers. If you are someone who mentors or teaches junior developers, I encourage you to try focusing more on testing. The results may surprise you.