Why Test-Driven Development (TDD) Benefits Junior Software Engineers

Test-Driven Development (TDD) is a software development approach introduced by Kent Beck in the late 1990s.

TDD is:

A software development process driven by the repetitive cycle of: listing tests, writing a test, making it fail, writing code to pass the test, and refactoring if needed.

To learn more about TDD, you can check out this article here or read the book Test-Driven Development by Example by Kent Beck.

At first glance, it might seem like extra work to write tests before writing the actual code. However, I believe TDD can greatly help junior software engineers better understand and navigate the software development process.

Why? Let me explain.

My journey with TDD began when I was a software engineer at a startup. Our team didn’t write any tests. We’d just code, do some code reviews, and push to production. Initially, it felt fast and fun. But as the codebase grew, it became increasingly difficult to maintain, refactor existing features, and add new ones.

Our team started encountering a lot of bugs, all over the place, which even disrupted our current sprint development. During our retrospectives, we discussed how to solve this problem. One team member suggested we start using TDD. And at that time, I was assigned the task of learning and implementing TDD for our team.

So, I began learning TDD by reading books, articles, and trying it out myself. After this learning process, I created a workshop for our team to explain what TDD is, how to do it, and how it might help us solve our problems.

But I’m not here to talk about how TDD was implemented in our team back then.

It’s just that after developing with a TDD mindset for some time, I started thinking that TDD could really help juniors become better software engineers.

1. Think Like a User

In the initial stage of TDD, we need to list all the test cases that our code needs to cover.

This is where a junior software engineer can learn to think from the user’s perspective. What does the user want? What do they need? How will they use this feature? It forces us to think about the user before even writing a single line of code.

Ultimately, this means we can cover as many real-world scenarios and user perspectives as much as possible. First, we might consider things we hadn’t thought of before. Second, we could prevent certain bugs from happening in the future.

2. Write Maintainable Code

One of TDD’s core principles is to write the simplest code that makes the test pass.

We intentionally make the test fail first, then write just enough code to make it pass. After that, we ask ourselves: Can we refactor this to make it better? If yes, we refactor. We repeat this process until we’re satisfied with the code.

For me, this process makes me more thoughtful when writing code. I’m forced to write the simplest version first, and then I re-read the code and ask: Can I make it better? More readable? More maintainable?

3. The Power of Tests

One of the most crucial parts of TDD is the tests themselves.

Writing tests provides several benefits:

• Automated testing: Tests can be run automatically anytime.
• Documentation: Tests act as living documentation for your code.
• Regression prevention: Tests help ensure new changes don’t break existing functionality.

So, How Does This Help Juniors?

Let me be clear: TDD isn’t a silver bullet for software development. You can use TDD and build great software, and you can also build great software without using TDD.

For senior engineers, you likely have a wealth of experience. You know what to do, how to do it, and the potential impact of your decisions.

But for juniors, it’s different. They’re still learning, still searching for best practices, and still trying to find the most effective ways to develop software.

TDD is a discipline that can help juniors learn and understand the software development process more deeply. It encourages them to think from the user’s point of view at the first place, write maintainable code, and test their code throughout the development cycle. Most importantly, having tests in place can significantly minimize the bugs that occur. This benefits the business, the users, and the developers themselves.

And perhaps, once they’ve gained a better understanding of the software development process, they can choose whether or not to use TDD. But at least they’ll know what TDD is, how to practice it, and how it can aid development.

So yes, I believe that:

TDD is an excellent discipline for junior software engineers to produce high-quality software while learning the software development process better.