Digital Transformation
Test-driven development
The whole exists only because there are parts that interact with one another. When we sharpen our perception and apply this line of thinking to systems, we see them as a set of screens containing buttons that perform functions and trigger other functions… We can break down the entire application into very small parts. To inspect them, we perform unit tests.
In the post about testing that we published here on the Inmetrics blog, we pointed out that we typically organize them based on two types of classifications: “who” and “what.”
Like any other type of testing, unit testing can be either automated or manual. In this article, we will highlight the importance and unique characteristics of unit testing, how it is typically conducted, and the extent to which it contributes to the development of new digital products or the transformation of legacy systems when it is part of application modernization projects.
The key feature that distinguishes integrated tests from unit tests is their level of granularity. Generally, unit tests are performed on isolated functionalities, without considering their connection to other parts of the system, services, or external agents.
Naturally, unit tests run faster. This premise is also consistent with a digital business development approach that gained popularity just over a decade ago: “test fast, fail fast”—concepts from the “lean startup” movement.
This principle makes sense given the primary goal of unit testing: the early detection of defects. By testing and validating components independently, a “safety net” is created around subsystems, preventing errors from propagating to higher levels of the application.
Broadly speaking, there are four basic principles of unit testing:
It is worth noting the fourth principle, given that we mentioned at the beginning of this text how tests are typically classified. The more independent they are, the easier they are to automate. Manual tests will, to a large extent, be more common within the spectrum of user-centered tests, such as experience, usability, and accessibility testing.
When unit tests are performed, we become more efficient at identifying the causes of errors. This benefit can be even greater if teams adopt a test-driven approach.
When we discuss manual testing here on the Inmetrics blog, we introduce the test-driven development approach—known by the acronym TDD. In this approach, which was originally proposed for automated unit testing, the test is written before the code. In other words, the inspection of each component is itself the criterion for higher-quality development.
In a case study conducted by researchers at IBM and the University of North Carolina, it was demonstrated that the unit-test-driven development approach reduced pre-release defect density by 40%, thereby offsetting the time that would have been spent on future debugging. In other words, testing and failing fast at the component level accelerates project delivery.
Efficiency gains are even more critical in today’s landscape, given that modern application architecture is based on microservices and that the guiding principle for companies at the forefront of systems development is continuous inspection and improvement. Unit testing has therefore become a key component of quality-as-a-service, enabling the constant monitoring and review of applications.
And in the current landscape—the Age of Artificial Intelligence —this constant monitoring and review is already being carried out by AI agents that use LLMs for mass testing. The AI itself generates the tests it will run as it develops the code.
Here at Inmetrics, precision is at the heart of what we do. Working methodically to deliver results is one of our core principles. As a result, we approach testing with a balance of rigor and judgment to ensure the quality of the applications we build.
Our Digital Experience business unit is focused on developing solutions that enhance the end-user experience. We combine quality engineering with artificial intelligence to prevent and anticipate any friction points along the user journey.
If your company needs to conduct large-scale software testing or assess the feasibility of modernizing legacy systems, contact us and speak with one of our experts! We have tools to thoroughly inspect an entire application and, as a result, accurately estimate how long your application modernization project will take. Click here to contact us!
