7 best practices for Agile Test-Driven Development

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Kent Beck, in his book ‘Test Driven Development: By Example’, says, If you’re happy slamming some code together that more or less works and you’re happy never looking at the result again, TDD is not for you. TDD rests on a charmingly naïve geekoid assumption that if you write better code, you’ll be more successful. TDD helps you to pay attention to the right issues at the right time so you can make your designs cleaner, you can refine your designs as you learn.” 

TestDriven Development (TDD) is a minimalistic software development process in which the tests are written before the actual code. By doing so, the method ensures maximum alignment between the requirements and the production code. In a TDD software development process, the requirements are converted into highly specific test cases that define the features needed. Then, code is written based on the feature-driven test cases. When the tests are written before the code, the developers can focus better on the requirements and specifications.  

First, the code is written to fail the testOnce the test fails due to the expected reasons, the developer then writes a minimal code to pass the test case. All the test cases should pass individually as well as in compilation and should not break or affect any existing feature or functionality. Then the code is refactored to meet the standards and duplicates are removed from the code base. TDD software development process results in a flexible, and bug-free code, high test coverage, and greater productivity of the tests. Designed as an offshoot of extreme programming, TDD follows the agile method of building software in iterations and involves clean, simple designs and code. 

Let us talks about some of the best practices to be followed in TDD projects: 

1. Avoid functional complexity

Focus on one functionality or feature at a time – keep it simple! Deliberate on it with the whole team to ensure the test case covers the desired functionality in every way possible. As the test case is the driver here, it should be reviewed for correctness and completeness. 

2. Focus on what you need to achieve

Make sure that you understand where the code needs to be called and frame the test suite accordingly.  Ensure test cases follow standard naming conventions and clearly depict what needs to be achieved by the end of the development process. This is crucial as functionality keeps getting added with iterations. Future developers should be able to look at the test and easily deduce the intended functionality. 

3. Maintain code austerity

Ensure your code has just enough meat to satisfy your test case. This is a basic tenet of TDD. This minimizes the chances of defects and also simplifies review and testing processes. However, do ensure the code is understandable and allows future enhancements. 

4. Test repeatedly

Test before coding and after coding. Then test once again after code refactoring. This is to reinforce that no code is broken in any of the steps. During refactoring, ensure the new code is maintainable and adheres to the standards. The rule of thumb here is to repeat testing whenever there is a code change or code move or code merger. 

5. Maintain code sanctity

Use version control tools to check out and check in code. This is important, specifically when more than one developer is working on the code. Using continuous integration tools like Jenkins can avoid code merger issues. 

6. Application knowledge

In TDD, coding needs to be limited but effective in that it achieves its purpose without breaking anything else. Also, the new code should ideally pass the test case in the very first run. Maintaining adequate system documentation, including a repository of test cases and engaging team members with good application knowledge can ensure a smooth and successful project execution. 

7. Know when to use TDD

Last but not the least, TDD, like any other development concept, works best in certain scenarios. Use TDD for developments that can be quickly tested. Any testing that is prolonged or complex defeats the purpose of TDD. 

To sum up 

With TDD, development is more controlled and as a result, defects are considerably reduced. Repetitive testing ensures each component in the system is working correctly at every step. Test-driven development is a perfect choice for functional testing but may not be sufficient when it comes to complex situations such as with UI testing. TDD, if understood properly, is the simplest way to achieve high test coverage and better code quality. 

Cigniti’s Distributed Agile Testing Framework is a global delivery model that helps in setting up frameworks for enabling enterprises test for agile implementations and best practices including Scrum, Acceptance TestDriven Development (ATDD), BehaviorDriven Development (BDD), Scaled Agile Framework (SAFe), Scrum of Scrums (SoS), and more. Our matured and proven test approach helps our clients seamlessly integrate their agile development processes and hybrid development processes. Schedule a discussion with us to understand how we can help your enterprise.