Unit testing is a key part of the software development lifecycle as it ensures that the software is working to expectation. Within your team, you run this testing unit by unit to individually verify the accurate function of each unit.
Because of its importance, companies invest a significant amount of resources towards unit testing. A 2021 survey found that 44 percent of companies spend more than eight hours a week testing code. While this might seem like a steep investment, properly running software is essential for maintaining a high quality user experience.
In this article, you’ll learn more about what unit testing is, the different types, and how to implement it within your product team.
Unit testing is a testing method in software development where each individual part (unit) of an application is tested to analyze its proper working. This approach is pretty common and used by most development teams to verify the accuracy of each software component.
This is done to test the efficiency of each unit before it’s integrated with the rest of the application. Key aspects of unit testing include:
The isolation of each piece of code helps to detect errors at the earliest stage. This practice helps save resources and ensure that every part of the software is reliable in the long run.
Unit testing is conducted in three different steps. Each step is closely related to the other and is crucial to carry out the entire process properly.
At this stage, the developer defines the objective and scope of the testing. Once the unit of application is identified, the developer also defines the criteria for testing it. Critical thinking and effective planning is needed at this stage to ensure focused testing.
The next step is to write the test cases for the unit. Test cases are testing scenarios against which the software unit’s functionality is tested. Think of it as the questions that the user might ask the software and the software will provide answers for it.
For instance, let’s say you are unit testing the calculator software for a web app, when adding two numbers, does the equal button give the right answer? However, test cases are not always straightforward. There are edge cases as well.
An edge case refers to the occurrence of an extreme scenario during the normal expected working of any software. They are often the rare events that can happen when a user is using the software application.
The test cases should cover both the normal and edge case conditions of the software unit. This helps to pinpoint the flaws and errors in the code.
Once the test cases are crafted, the ultimate stage is the testing itself. This involves testing the scenarios and deeply analyzing the results. Successful execution of test cases validates the reliability of the unit under different conditions.
If certain edge cases are not handled by the software, they need to be addressed (depending on their criticality) before moving forward with development.
Unit testing can be done manually or can be automated. Both approaches have their pros and cons. Manual unit testing involves developers writing and using test cases to check the proper working of each software unit.
Automated unit testing on the other hand uses software tools to execute predefined test cases against each unit. Here are the key differences:
Most software teams are slowly, but surely adopting automated testing techniques.
If done properly, unit testing offers many benefits to enhance the overall quality and dependability of any software.
Individual component testing helps developers detect problems and bugs at a very early stage in the software development process. This eliminates the risk of accumulating a backlog of unaddressed issues.
Unit testing saves time and money for the company in the long run. Bug fixes at later stages in the development lifecycle are always expensive to treat.
When a unit test fails, the developers can easily identify its root cause and fix the issue. This precise debugging is made possible with unit testing where developers get to spend more time fixing stuff instead of finding the problems.
Unit testing is more than testing as it also acts as documentation for the software. Unit tests demonstrate the actual working of software. This can help developers maintain and understand the codebase with ease.
Such a level of transparency and clarity supports code reusability as well. New developers can quickly gain knowledge of how existing components work. Unit testing also sets the base for how to reuse and modify the existing components for new projects.
Ultimately, adopting unit testing practices leads to major improvements in both the short-term and long-term success of software projects.
Unit testing is a crucial component of software development, but it does come with certain disadvantages.
While unit testing is very useful for ensuring software quality and reliability, always consider these limitations. These limitations might be more problematic depending on the nature of the software project.
In large scale software projects, unit testing plays a considerable role. For instance, the open-source project called “Apache Hadoop” relies heavily on rigorous unit testing. Similarly, in C++ development, many frameworks like Gtest and Catch2 are heavily relied upon to manage the testing phase.
Software testing at a unit level ensures reliability of the application. Reliability is arguably the key difference between a good software and a bad software.
Unit testing is often supported by a wide range of tools and frameworks. Each has its own specific purpose and adds to the testing process in a unique way. Some tools and frameworks are language-specific and provide dedicated assistance for that tech stack.
Frameworks and tools aid developers with test case creation, execution of testing cycles, and result analysis. Some of the tools are:
Integrating these tools into the development workflow is becoming more popular. These tools can speed up the process for both automated and hybrid testing models.
Unit testing stays relevant and useful in the realm of software development. It acts as a first line of defense against resource leakage, by identifying complications at a unit level. It helps the software development teams through:
Automation practices might change the way that unit testing is carried out but its importance can not be overstated.
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