Test-driven development (TDD) is a software development process that follows a short, repetitive, and continuous cycle of creating unique test cases for what companies want in their web or mobile application, then writing code to actually produce it with quality. Test-driven development differs from traditional QA testing because very specific test cases are written first based on what companies want to see in their application, then, the engineers write code with the goal of making that initial test pass.
Unlike traditional software testing, where QA processes are siloed towards the end of development, test-driven development implements testing before and during development. This makes TDD highly compatible with fast-moving, iterative development styles, such as Agile and Continuous Deployment.
Test-driven development provides multiple benefits, including:
Small amounts of code are written and tested at a time, ensuring that almost every individual line of code is NOT producing a bug or defect. If hundreds or thousands of lines of code are written at a time and before being tested, bugs and defects are likely to be found much later in the software development life cycle or when the code has already been shipped to production. This longer feedback loop can make it harder for engineers to fix the problem without altering other parts of the code and creating bigger issues.
Because in a TDD process test cases are written and refactored alongside the code rather than requiring a separate cycle, the team can save time and resources in the long-term. Since the entire code base is inherently covered by the TDD process, there is a better chance that every part of the application will have an acceptable amount of coverage.
Test-driven development requires a significantly shorter amount of time to write code because the unique test cases act as instructions and guidelines for the engineers. Spending the time thinking through the unique test cases from the start reduces time writing code for that test later on because what is being created is less error-prone. Each test case also serves as a measurement of success when the code yields passing results. TDD saves time, so efforts can be focused on other pressing matters of the business. Because feedback on code quality is given very quickly, test-driven development can also decrease disruptions to developers’ workflows.
Test-driven development is good for teams that have fast release cycles, but still want to ensure their customers are receiving quality results with every change made. With an aggressive cycle of continuously writing code and wanting to ship it to production, these companies need to minimize the amount of time they spend doing quality assurance testing so that their development cycle is not halted due to testing.
Second, it is beneficial for companies that have little to no in-house QA practices instilled, but still value quality for customers. Test-driven development is a great first step in implementing QA practices within a developer’s workflow.
As shown in the figure below, the process begins with creating a unique test case based on a new feature update the company would like in their web or mobile application; as expected, that test case will fail. Code will then be written based on what the test requires. If the test fails again, the code must be refactored and the process starts over. If the test passes, one can optimize existing code or add new code based on new features that want to be implemented, and the process starts over.
New test cases are always being written because features are always being added, updated, and changed in the application. One of the most important parts of this cycle is that it repeats itself throughout the application’s lifetime in order to build coverage. Instead of going through this cycle after large chunks of code are written, it should be repeated for almost every change made in the code.
Individuals on product teams will always have different approaches to writing code and testing it. Because TDD is continuous and allows engineers to take smaller steps when coding, it is important that everyone involved in the development of features is willing to move at a faster pace; it can be hard to get everyone on the same page. It is also important because when multiple engineers are working on the code, there needs to be transparency of when the code is done being written, if it has been tested, and if it needs refactoring.
With more feature additions and updates being shipped to production, the more important communication becomes with not only everyone in the company, but with customers as well. It is vital that all customer-facing teams within the company (i.e. Sales, Marketing, Customer Success, and Product) are fully aware of these changes and understand what value they can provide customers. Because the development cycle is faster with test-driven development, it is easier to lose track of everything, therefore more difficult to communicate with the company and the customers.
To switch to a test-driven development process takes an initial acclimation time for everyone involved in the product development side. To train everyone on a faster-paced development cycle and figure out methods of communication, will take some trial and error. This initial ramp-up time is what will be time and effort intensive. Product teams can find themselves crunched for time in these beginning stages, especially if they are having to do all the QA testing themselves; the product team can potentially lose sight of other important business matters during this acclimation period.
Rainforest QA is able to assist product teams by quickly testing their code for them. Users do not require technical expertise to use the Rainforest platform, so it is simple for anyone to create unique test cases and run the tests whenever necessary.
Utilizing the platform has allowed many companies to increase the efficiency of product teams by implementing test-driven development in their software development lifecycle.