What is Unit Testing in Software Testing? [Definition Simply Explained]

What is Unit Testing?

Unit testing is a type of testing that focuses on verifying the behaviour of individual units or components of a software system.

Unit testing is an important aspect of the software development process to identify and verify the bugs at an early stage. This way, you can improve the overall quality of the software application. A few unit testing techniques are test-driven development, behaviour-driven development, white box testing, black box testing, and gray box testing.

Apart from unit testing, there are different types of software testing to completely ensure that the software is bug-free and meets the performance benchmarks.

You can read this guide on different types of software testing to know how software is checked in different scenarios. Going through our guide helps you to build a strong understanding of software testing and how different tests are important before deployment.

In the next section, learn about the key components of unit testing.

What are the Key Components of Unit Testing?

Here are the key components of unit testing that help you to perform unit testing.

  1. Test cases: These are sets of inputs and expected outputs designed to verify if a specific source code behaves as per requirements.
  2. Test suite: A collection of test cases that are designed to test the functionality of a specific unit or component.
  3. Test runner: A tool that executes test cases and collects the results, such as pass/fail status and other relevant information.
  4. Test framework: Unit testing frameworks offer the infrastructure and tools necessary for automating the unit testing framework. This includes libraries and testing tools for creating, executing, and reporting on tests.
  5. Assertions: Statements in test cases that compare the actual output of the code being tested with the expected output.

How Does Unit Testing Work?

Unit software testing can be performed either manually or using automated tools. However, automated unit testing is more efficient and widely used in modern software development processes. If you are unaware of automated testing, read this article on what automation testing is.

Let’s now learn about the steps that are executed for unit testing. Here is the list of steps that are executed for unit testing.

  • Identify the unit or component to be tested.
  • Writing tests for the unit, covering various scenarios and edge cases.
  • Run the unit test cases using a test runner.
  • Analyze the results and fix any issues identified.
  • Repeat the process until all test cases pass.

7 Benefits of Performing Unit Testing

Learn about the core advantages of conducting manual or automated unit tests.

  1. Reduce the Development Time to Launch Early

    By identifying and fixing issues early in the development process, unit tests reduce the time and effort needed for debugging later on, resulting in faster development cycles.

  2. Improve the Quality of Code to Provide Robust Performance

    By identifying and fixing issues early in the development process, unit tests reduce the time and effort needed for debugging later on, resulting in faster development cycles. Unit testing helps to ensure that individual components work as per requirements.

    That means each test case is tested independently to ensure it works correctly. So you can develop a more stable, reliable, and robust software application. Your software testing doesn’t end here as software developers are only checking individual code components at this testing.

    However, you need to ensure your software as a whole works fine and provides you expected results. This is where integration testing is done. Read this definition post on what integration testing is.

  3. Make the Maintenance of the Software Easier

    The code of a software application gets thoroughly unit tested. Generally, as a tester, you need to make the code of an application easier to understand, modify, and maintain over time. Therefore, you can assure that the application provides the expected behaviour and works according to predefined requirements.

  4. Build Better Coordination and Collaboration With the Team

    Unit tests serve as a form of documentation for the intended behaviour of the code, making it easier for other software developers to understand and work with the codebase. This promotes better collaboration among team members.

  5. Detect the Hidden Bugs or Issues With Regression Unit Testing

    Unit tests can be re-run whenever changes are made to the codebase. By performing regression unit testing, you can identify any regressions or unexpected side effects caused by modifications to the code. This helps you to resolve the issues that were previously not detected.

  6. Optimize the Code of the Software to Ensure Quality Refactoring Support

    Unit tests provide a safety net when refactoring or optimizing code, as they help ensure that the functionality remains intact after changes are made.

  7. Develop the Reliability and Stability of the Software

    Thorough unit testing gives developers and stakeholders confidence in the application’s stability and reliability. By providing better user satisfaction, you can ultimately provide a more successful product.

Next, let’s learn about the best practices to perform effective unit testing.

5 Best Practices for Unit Testing

Here are the 5 best practices to follow while conducting unit testing.

  • Write test cases for both positive and negative scenarios, including edge cases.
  • Keep test cases simple and focused on testing a single aspect of the unit’s functionality.
  • Use descriptive names for test cases to communicate their purpose.
  • Follow the Arrange-Act-Assert (AAA) pattern when you write unit tests. This involves setting up the necessary preconditions (Arrange), executing the unit being tested (Act), and verifying the expected outcome (Assert).
  • Use mocking or stubbing techniques to isolate the unit being tested from external dependencies, such as databases or APIs.

In conclusion, unit testing is important to ensure software quality and reliability by testing individual components independently. It helps to identify and fix issues early in the development process, so you can develop a successful product.

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Rakesh Patel

Written by

Rakesh Patel is the Founder and CEO of Space-O Technologies (Canada). He has 28 years of IT experience in business strategies, operations & information technology. He has expertise in various aspects of business like project planning, sales, and marketing, and has successfully defined flawless business models for the clients. A techie by mind and a writer at heart, he has authored two books – Enterprise Mobility: Strategy & Solutions and A Guide To Open311

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