What is the difference between unit testing and integration testing?

Unit testing is one of many types of testing performed during the early stages of software development. Some other common types include:

• Integration testing

• Systems testing

• Acceptance testing

• Regression testing

• Performance testing

In the software development process, unit testing and integration testing sometimes go hand in hand. However, when looking at unit testing versus integration testing, these two steps actually serve opposing purposes.^{Footnote 2}

Unit tests evaluate the function of individual components, while integration testing evaluates the functionality of a system containing many different components. One looks at the pieces, and the other looks at the whole.

Unit testing tutorial curriculum

A tutorial on this topic can cover the basic elements of unit testing as they relate to the language you are learning. For example, in a Java course, you would learn the purpose and framework of Java unit testing. Similarly, learners in a C++ course can expect to cover C++ unit testing frameworks and uses.

Beginner and intermediate unit testing curricula can cover the following:

• An overview of unit testing

• Testing frameworks & unit testing tools

• Guidelines for how to write unit tests

• Test-driven development guidelines

• Code coverage

• Unit testing automation

edX offers online courses that allow learners to study a variety of topics including computer science, web development, and much more. Sign up for an accelerated boot camp or enroll in a full degree program and start working toward a bachelor's degree or (for more advanced learners) a master’s degree in a relevant subject. You can also explore executive education programs specifically designed for busy professionals.

Explore unit testing jobs

From hands-on developers to executive leadership roles with a technology focus, there are many job opportunities at all levels that utilize specialized skills in unit testing, including: 

• Software developer: Writes code to create a program or application. Developers use unit tests as a routine tool to proof their code and catch errors. Many developers have sub-specialties in specific programming languages, or with a specific tech stack. For example, a Python developer might learn Python unit testing.^{Footnote 3}

• Quality assurance engineer: Uses unit testing as a tool to evaluate and score software products, ensuring consistency and functionality.^{Footnote 4}

• Software architect: Oversees the planning and design of large software development projects. The architect might use unit testing methodology to ensure that their designs are testable.^{Footnote 5}

• Technical lead: Supervises a development team and oversees the entire development project. The technical lead will use unit testing to ensure that the code provided by each developer on the team is functional.^{Footnote 6}

Completing a coding boot camp can be a great way to build skills you will need for technical roles such as a software developer, architect, engineer, or technical lead. However, the required skills and qualifications for each of these roles will vary based on the position and employer. 

How to use unit testing in your career

Developers can use unit testing to improve the quality of their code and demonstrate proficiency in their job. The precise applications of unit testing depend on the programming language. This might include sub-specialties like:

• Unit testing in C#

• Python unit testing

• JavaScript unit testing

• C++ unit testing

So, what is unit testing in software engineering? It is a measure of quality assurance that helps improve the quality of programs and applications by providing a streamlined, efficient method of identifying small errors in the code so that the developer can quickly correct them.

edX offers a variety of learning opportunities to help developers gain specialized skills like unit testing to increase their employability and earning potential. Programs in Python development, JavaScript development, or C++ development can be a good way for learners to progress in technical roles.