Understanding Branch Coverage in Software Testing

Cover Image for Understanding Branch Coverage in Software Testing
Arindam Majumder
Table of Contents


Branch Coverage is a popular testing technique that provides insights into the percentage of branches executed during testing.

In this article, we'll explore what is Branch Coverage, Its importance, How it works, and many more!

So Without delaying further, let's Start!

What is Branch Coverage?

black flat screen computer monitor

Branch coverage is a white box testing technique to measure which branches (decision points) in a program's code have been executed during testing.

A “branch” is one of the possible execution paths the code can take after a decision statement—e.g., an if statement—gets evaluated.

Formula of Branch Coverage:

Branch Coverage (%) = (Number of Functional Flow Implemented & Tested)/ (Total Number of Success & Fail Conditional Flow) * 100
A program with high test coverage is more likely to have fewer bugs compared to a program with low test coverage.

Let's Understand that with an example,

  if (condition1) {
      if (condition2) {
          // block 1 
  } else {
      // block 2  

There are 4 possible branches here:

  1. condition1 and condition2 are true -> block 1 executes

  2. condition1 is true but condition2 is false -> block 1 does not execute

  3. condition1 is false -> block 2 executes

  4. condition1 and condition2 are false -> block 1 does not execute

To achieve 100% branch coverage, we need test cases that execute all 4 paths.

How does it work?

black flat screen computer monitor

Branch coverage works by analyzing the flow of control in a program. Here are the steps:

  1. Firstly, we identify the branches in the code.

  2. During the Testing phase, It uses tracking to see which paths the program takes during tests.

  3. Now the Test cases are run on the instrumented code.

  4. After the test execution is complete, the tool collects data on which branches were executed and how many times.

  5. With that data, the branch coverage percentage is calculated using the formula (mentioned before).

Why it's Important?

Branch coverage is an important software testing metric. It has many benefits, Here are some of them:

  • It helps us to find which branches are not tested. So, we can easily fix potential bugs.

  • High branch coverage states that most of the code has been tested which also indicates that our code is more reliable.

  • It reduces the likelihood of edge-case defects

  • It improves the maintainability of the code.


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Thank you for Reading 🙂

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  • Arindam

    As a DevRel Intern at Keploy, a tool for automating writing manual Test cases, I am responsible for creating and delivering engaging and informative web content and technical documentation for our users and partners. I use my skills in web development, content creation, and public relations to produce high-quality tutorials, blogs, videos, podcasts, and newsletters that showcase the features and benefits of our platform and help our users solve their deployment challenges. I am also a passionate tech blogger and an open-source enthusiast, with over 50 blog posts published on various platforms, reaching over 100,000 views and 10,000 claps. I write on topics such as open source, web development, and data structures and algorithms, to share my knowledge and passion with the tech community. I have also participated in several open source programs and events, such as Hacktoberfest, Google Summer of Code, and MLH Fellowship, where I have contributed to various open source projects and learned from experienced mentors and peers. I am currently pursuing my B.Tech degrees in Information Technology and Computer Science at MAKAUT and Heritage Institute of Technology, respectively. I am eager to learn new skills and technologies and apply them to real-world problems and solutions. I am also interested in exploring the fields of artificial intelligence, machine learning, and natural language processing, and how they can enhance the user experience and the social impact of web applications. My goal is to become a full-stack developer and a leader in the tech industry.


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