As a dedicated practitioner of Test-Driven Development (TDD), I firmly believe this approach has been instrumental in advancing my career. It has significantly enhanced my developer experience and made my day-to-day tasks more manageable.

In this article, I’ll share how TDD has positively influenced my daily work, focusing specifically on its benefits to the developer experience. I’ll avoid discussing the technical advantages and instead highlight how TDD has improved my workflow and overall productivity.

Let’s start with a brief overview of TDD.

What is Test-Driven Development (TDD)?

Test-Driven Development (TDD) is a methodology where the implementation of a system’s behavior is driven by creating tests that serve as executable specifications.

That might sound complex, so let’s break it down with an example. Suppose you have a conversation with your users, and they describe a feature they want. You take this feature and jot down its various use cases on a piece of paper, a to-do list, or as a comment in your test file.

You start by writing a failing test for the first use case. Then, you write the minimal amount of code needed to make that test pass and refactor the code to improve it. Next, you translate the following use case into a failing test, write the code to make it pass, refactor, and continue this process until the entire feature is implemented.

This straightforward approach offers numerous benefits.

How TDD Enhances Domain Knowledge and Understanding

Decomposing tasks and thinking about the next test to write has encouraged me to ask insightful questions and delve deeper than the information provided in user stories or Jira tickets. This process pushes me to step out of my comfort zone and engage with domain experts, users, designers, and other stakeholders.

As an anecdote, a client in the energy market once mentioned that our calculations were more accurate than those of their legacy system, simply because we considered every possible case.

Simplifying Complex Projects

Some domains are inherently complex, and breaking them down to learn incrementally helps effectively manage this complexity.

Additionally, some solutions can be quite complicated, but TDD makes it easier and more confident to refactor, allowing us to explore various solutions and potentially discover simpler ones.

Achieving Peace of Mind: Refactoring and Feature Expansion Made Easy

Having tests as a safety net allows me to refactor confidently and add new features without worrying about breaking existing functionality. I can push code knowing it aligns with user expectations or, at the very least, our team’s understanding of the requirements. When something breaks while changing the code, I am certain it was due to the most recent change, and I can easily revert to the last passing state.

Accelerating the Feedback Loop

One of the challenges I faced in my early coding days was the tedious process of manually iterating while developing a feature. The typical scenario looked like this:

  1. Fill out the fields of a form.
  2. Submit the form.
  3. Run a GET request to check if the data is restored correctly.
  4. Clean the database and start over.

I had to repeat this for every possible scenario. To put it mildly, this method was a nightmare. It involved a prolonged feedback loop and wasted a lot of time (think of all those clicks!). With TDD, I write a test for the use case and run it as often as needed until I’m satisfied. If there’s a different input, I can parameterize the test; if there’s a combinatorial explosion, I can isolate the code and test all the different use cases on it.

The added bonus is that all of this is repeatable in the future.

Enhancing Workflow Flexibility: How TDD Helps with Interruptions

By keeping a list of tests, you always know your current progress and what still needs to be implemented. If a test is failing, it clearly indicates the next step in your workflow. This structure is especially helpful when you’re interrupted—whether it’s by a teammate or a break—allowing you to quickly pick up where you left off without overthinking.

These are the main ways in which TDD has benefited me, though other practitioners might have experienced additional advantages depending on their projects. For me, these are the standout benefits of incorporating TDD into my workflow.

And how about you? What’s the one practice or lesson you’ve learned that has had a significant impact on your career?