Unit Testing 101 (Part 1) with AgileTest

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Writing good code is not just about making it work – it is about making sure it keeps working. Unit testing helps you catch bugs early by testing each piece of your code separately.

In this blog, we at AgileTest for Jira will break down unit testing in plain narratives: what it is, how it works, and why it matters for your projects. 

-> Read full article for code guidance here: Improve Code Quality with JUnity

What is unit testing?

Unit testing involves evaluating the smallest functional parts of code to ensure their quality. It is a crucial practice in software development, where the code is broken down into small, functional units, each accompanied by a corresponding unit test. 

These tests are written as code and can be run automatically whenever the software is updated. This approach allows developers to quickly identify and isolate bugs when a test fails. Unit testing promotes modular design and increases the overall quality and test coverage of the code. Automated unit testing also frees up more time for developers to focus on writing new code.

What is a unit test?

A unit test is a segment of code that checks the correctness of a smaller, isolated portion of an application, typically a function or method. It aims to confirm that the code executes as expected based on the developer’s intended logic. Unit tests interact with the code only through inputs and evaluate the output using assertions (true or false conditions).

A code block can have multiple unit tests, referred to as test cases, which together aim to cover the full range of expected behavior. However, defining a complete set of test cases is not always required. Unit tests must operate independently, meaning they should not rely on other parts of the system, such as databases, objects, or network communication. If the code depends on external data, data stubs should be used. Writing unit tests is more straightforward for smaller, logically simple code segments.

Types of unit tests

Different types of unit testing are designed to address these challenges individually. Each type offers unique advantages for identifying and resolving specific kinds of issues.

White-Box Testing

White-box testing, also known as structural or clear-box testing, is a testing method that examines the internal structure and workings of the code. 

Testers here are not just scratching the surface. Instead, they analyze code structure, control flows, and specific logic paths with a thorough understanding of the programming language and system architecture. Because of this level of detail, white-box testing becomes especially effective for syntax errors and boundary issues. 

Black-Box Testing

Black-box testing, sometimes called functional or specification-based testing, is the method of evaluating the software’s external behavior without regard to its internal code structure. Instead of focusing on how the code is built, black-box testing examines whether the code performs its intended functions.

Here, testers evaluate whether the software meets its functional requirements without looking beneath the surface. This makes black-box testing particularly useful for ensuring the software performs as intended under various conditions, while also uncovering usability and accessibility issues along the way. 

Gray-Box Testing 

Gray-box testing, meanwhile, combines elements of both white-box and black-box methods, offering a balanced approach by using partial knowledge of the system’s internals to guide testing. 

Testers have limited knowledge of the code’s internal structure, allowing them to identify issues in data flows and application behavior while still maintaining a degree of objectivity and focusing on the external functionality. Additionally, this approach fosters communication between testers and developers, enhancing the overall effectiveness of the testing process.

How Developers Utilize Unit Tests

Test-Driven Development (TDD)

In TDD, tests are written to meet functional requirements before the actual code is developed. Once coding is complete, the code is tested against these predefined tests to confirm it meets the specified requirements.

Post-Coding Testing

When a block of code is completed (if not already covered by TDD), unit tests should be written to verify its functionality. Unit tests are the first set of tests run during system testing and form part of the comprehensive test suite.

DevOps Integration

In DevOps practices, unit tests play a key role in continuous integration and continuous delivery (CI/CD). They automatically run alongside other tests in the CI/CD pipeline to ensure code quality during ongoing development and deployment. 

AgileTest – Enterprise QA and Test Management in Jira elevates test management and quality assurance by connecting your Git workflow with automated test management. When tests run in Bitbucket CI/CD pipelines, AgileTest automatically imports and analyzes the results, linking them directly to the Jira issues in real-time. This integration updates test execution statuses and can trigger automated actions in Jira based on test outcomes, eliminating manual reporting steps. By seamlessly connecting Git, Bitbucket, and Jira, AgileTest ensures your development and testing processes stay synchronized while maintaining clear visibility of your test coverage.

Conclusion

We have covered how to break down and test your code effectively, which tools can help, and how to make testing part of your daily development work. The goal? Building better, more reliable software with fewer headaches.