White box testing is a type of software testing that tests the internal logic of code or the “guts” of the software. This is different from black box testing, which only focuses on whether the user interface works as expected and does not require any knowledge of how it works. White box testing requires thorough knowledge of how the software works so you can test it at its source. Keep reading to learn more about white box testing and why it’s important in your software development process.

What is White Box Testing? #

White box testing (also known as structural testing, glass box testing, clear box testing, or transparent box testing) is a software testing technique that tests the code at the source level or “inside the box”. It is a type of “internal testing,” which means the code is tested by people who have access to its source code, either because they wrote the code themselves or they have privileged access to the code. The term “box” refers to the black box metaphor in computer science: a program’s input and output are like the two sides of a box, and the internal program’s code is like the walls inside the box. White box testing involves examining the code inside the box and testing it as if it were a black box.

Why Is White Box Testing Important? #

White box testing is a critical part of software testing for a couple of reasons. First, it’s the only type of testing that is certain to find all the defects in the code (assuming you have the right tools to use). This is because you can test at the source code level and you have access to the code’s design and implementation. Second, it allows you to test the design of the code as well as its functionality. The design of the code is just as important as the functionality because a poor design can create bottlenecks, bugs, and poor scalability. Whitebox testing can help you test the design of the code by examining its structure, flow, and conditionals.

Types of White Box Tests #

There are many different types of white box tests, but here are the most common: 

• Architecture and design walkthroughs
• Code coverage (including condition coverage, decision coverage, path coverage, and error coverage)
• Code reviews
• Code reading
• Code walkthroughs
• Defect probes
• Design and code reviews
• Functionality walkthroughs
• Interfaces (including manual and automated interface testing)
• Requirements walkthroughs
• Regression walkthroughs
• Scaffolding and data walkthroughs
• Software design reviews
• Structure and code walkthroughs

How To Perform White Box Testing #

White box testing primarily consists of four different activities: 

Architecture and design walkthroughs

Code coverage (including condition coverage, decision coverage, path coverage, and error coverage)

Code reading – Code walkthroughs Architecture and design walkthroughs are essentially architectural reviews and design reviews. They’re used to test the architecture and design of the software. Architecture reviews help you understand the big picture of the architecture and how it’s designed. Design reviews help you understand how the architecture is implemented and how the design is implemented. Code coverage is a set of tests that ensure you’ve tested all the conditions of the code, all the decision points, and all the paths through the code. The types of tests that are most commonly used to achieve code coverage include statement, decision, condition, and path coverage. Code reading is the process of reading the code and understanding how it works and how it’s implemented. It’s used to discover defects and hidden requirements in the code. Code walkthroughs are essentially architectural and design walkthroughs with code.

When to use white box testing? #

Since white box testing requires thorough knowledge of the code, it’s best to use it with mature code or code that’s been unit tested. You can also use it with new code that’s been well defined and reviewed. It’s important to use the right testing technique at the right time. Whitebox testing is a great strategy when you’re testing the software architecture and design, or if you want to test the code’s design and structure. If you want to test the functionality of the user interface, then black box testing is your best option.

Conclusion #

Whitebox testing is a critical part of software testing. It’s the only type of testing that is certain to find all the defects in the code, and it allows testers to test the design of the code as well as its functionality. While whitebox testing is most commonly used for testing the software architecture and design, it can also be used to test the code’s design and structure. White box testing is particularly useful when testing new or well-defined code.