An Introduction to Test-Driven Development

Test-driven development (TDD) is a software methodology that emphasizes writing automated unit test cases before writing actual code. Once the intended test is set-up, developers then write the minimum amount of code to pass the test case. This is quickly followed-up with developers cleaning the code to have better design principle. This methodology differs from the traditional approach to coding by combining writing code and tests at the same time.??

TDD does this by following short iterative development cycles known as “Red-Green-Refactor.”??

Red: This is setting up the blueprint for the intended code. Developers make a unit test case for a specific function, and then run it to make the test fail.???

Green: The green phase is where you implement code to make your test pass. Developers write a simple code that passes the test, regardless of the code design.??

Refactor: This is the highlight of the three-part stages, as developers refine their code into adhering to best design practices. The process then repeats itself until the project is complete.??

TDD iterative approach naturally supports agile practices, with each development cycle regularly delivering functional software. By emphasizing test cases upfront, TDD delivers robust code that has the desired function while remaining adaptable.??

Alternatively, there is a variation to TDD called Acceptance Test-Driven Development (ATDD). This approach adopts a more collaborative mindset between customer, developer, and tester. These three differing perspectives all have the end-user in mind and promote a product that meets the user’s needs.??

In this introductory article to Test-Driven Development, we will explore implementing practices, benefits, and challenges that come with this software approach.??

How To Implement Test-Driven Development??

Test-driven development is a great software methodology that brings many benefits, but a deep understanding of its best practices is needed to utilize it fully. This section of the article will cover some best practices advice from one of our engineers at Valore Partners, Mark Scott.??

Mark starts off by stating that teams adopting this methodology will need to make a time investment upfront. The main priority being to write well-written and clear software requirements for the initial test cases before writing any product code. He understands that many teams will see that implementing TDD requires too much time commitment. They would be correct when considering it in the short-term. The initial investment does require patience and increased effort up front; however, he argues teams will recapture this in the form of increased productivity in the long run.?

Mark continues that teams must keep tests relevant and up to date as the base code evolves. This can be challenging in agile working environments, where there’s an emphasis on delivering projects quickly. One way to mitigate this challenge is to leverage professional tools, specifically through Continuous Integration/ Continuous Deployment (CI/CD) methodologies. This can help automate the testing process whenever changes to codes are made, maintaining the higher standard of code quality.??

Test-Driven Development Benefits?

TDD offers many benefits, making it one of the top methodological approaches to coding.? Some examples of said benefits include:?

Less Defects: By providing strong initial test cases, it will help detect issues early in the development cycle. This helps reduce time and effort spent on debugging later in production?

Improved Code Quality: The iterative nature and testing encourage developers to write modular and testable code, allowing easier rewrites and maintenance??

Enhanced Collaboration: TDD requires developers, testers, and stakeholders to remain on the same page when producing the test cases. This ensures all parties intent remain align during the project??

Flexible Code: As the base code evolves or when requirement changes, developers have the safety net of test cases in ensuring the code function is correct??

Challenges of Test-Driven Development??

While there are many benefits of using TDD, there are also as many challenges. It’s worth remembering that this is only a methodology to approach software, not the only right way of doing so.??

Initial Time Development: The time spent producing code for the project is instead spent on producing test cases. If the tests cases too complex, it will slow down development time in the initial phase?

Limited Test Coverage: TDD specifically focuses on unit level testing, but it remains important to incorporate other types of testing such as integration, performance and end-to end scenario testing?

Maintenance Overhead: TDD relies on having good test cases to ensure the project develops smoothly, which can lead to maintenance overhead while attempting to keep tests updated as code changes?

Conclusion??

With proper implementation of test-driven development, software projects will have stronger code design compared to the traditional approach. It’s important to remember while adopting this methodology to have an open discussion with the team to ensure everyone is on the same page. This will lead to deciding on the correct software tools to quickly deliver projects using test-driven development, and to produce reliable test cases for reliable software architecture.??