Value of Code Coverage in Software Testing

Imagine this, you have conducted a penetration test on an application and didn’t find any kind of vulnerabilities. Sounds like a good sign right! But, is it? If you want to pass a meaningful judgment, the one thing that you can do is measure code coverage. Or you can also take a leap of faith and consider that the application is free from bugs. 

But that isn’t a chance that you can take as it puts your reputation at stake. It is always better to be safer than sorry and this is where code coverage steps in. Let us understand what code coverage is, what are its benefits, challenges and who should perform it in the first place along with some best practices in this blog.

What is Code Coverage?

Code Coverage is a metric which ensures accuracy and reliability of an application’s code base. It measures how effective the testing was and helps in finding the areas that require more focus to improve the functionality of an application. Code coverage reports list how much of the application code has been executed. 

You can calculate code coverage percentage using the below formula. 

Code Coverage Percentage = (Number of lines of code executed / Total Number of lines of code in an application) * 100

What are the benefits of Code Coverage in CI/CD?

Code coverage brings in so many benefits to the table. Here are a few of them:

• Faster time to market and better ROI
• Higher customer satisfaction
• Easy to maintain code
• Identifies bad and dead code
• Early defect detection and prevention
• Identifies code segment omission
• Helps in code refactoring
• Provides quantitative measure of code coverage
• Measures efficacy of test suite
• Identifies test omissions

Why is Code Coverage Analysis Important?

Code coverage analysis is a valuable tool for software development because it helps assess how thoroughly your tests examine your code. By running tests and measuring what percentage of your code is actually executed during those tests, you gain insights into the effectiveness of your testing strategy.

High code coverage indicates that a larger portion of your code has been tested under various conditions. This increases your confidence that bugs are less likely to be hiding in untested areas. It also helps prioritize your testing efforts by highlighting sections of code that haven’t been covered, which could be areas where new tests are needed. 

Who performs Code Coverage and when?

Typically, developers themselves perform code coverage analysis. It’s integrated into the development process, often run after they write unit tests for a specific code block or feature.  These unit tests are designed to target and exercise individual sections of the codebase. By running the tests and examining the code coverage report, developers can identify areas where their tests haven’t reached and iterate on their testing strategy to achieve a more comprehensive test suite.

Challenges Faced While Attaining Comprehensive Code Coverage

It is not easy to attain complete code coverage. Some of the most common challenges that teams face are

• Complex Logic and Edge Cases: Code with intricate logic or a multitude of edge cases can be difficult to design tests that cover every scenario.  Exhaustive testing of all possible inputs and outcomes might be impractical or even impossible.
• External Dependencies: Code that relies on external factors like databases, file systems, or user input can be challenging to test in isolation.  Simulating these dependencies or creating mock objects to represent them adds complexity to the testing process.
• Legacy Code:  Older codebases might lack proper structure or documentation, making it harder to understand and write effective tests.  Refactoring legacy code to improve testability can be a significant undertaking.
• GUI Interaction: Testing graphical user interfaces (GUIs) can be cumbersome.  Traditional unit tests might not be sufficient to capture the interactions between UI elements and the underlying code.  Specialized testing frameworks are often needed for thorough GUI coverage.
• Time Constraints: Balancing code coverage goals with project deadlines can be tricky.  Writing extensive tests takes time, and achieving very high coverage percentages might not always be feasible or the most productive use of resources.

Best Practices to Achieve Code Coverage

• Focus on Unit Testing First
• Prioritize Critical Paths
• Write well-structured code 
• Utilize Code Coverage Tools
• Integrate code coverage analysis into your continuous integration (CI) pipeline.
• Target Edge Cases and Error Handling
• Mock External Dependencies
• Refactor for Testability

How Big-3 Telecommunications Company Achieved Higher Code Coverage with Webomates?

Challenge

A Big-3 telecommunications company, faced challenges achieving sufficient code coverage within their Network & Shared Platform Solutions organization. Manual testing processes were time-consuming and inefficient, hindering their ability to thoroughly test all functionalities.

Solution

Their team partnered with Webomates to leverage our AI-powered testing services. This innovative solution seamlessly integrated with the team’s existing SonarQube static code analysis tool, a popular choice for many developers.

Results

Webomates’ AI-powered testing service significantly improved the team’s code coverage, exceeding 80%. Our CQ portal provided detailed metrics at various levels (file, directory, package) for the entire codebase, including newly added or modified code.

This granular data visualization empowered the telecommunications testing team to efficiently identify areas where test cases were lacking.  By pinpointing uncovered sections of code, the team could streamline their testing efforts and focus on creating targeted tests to fill the gaps. The detailed breakdown provided by Webomates, including lines, conditions, and branches, further enhanced the team’s understanding of code coverage.

Impact

Webomates’ AI-powered testing service not only boosted code coverage but also contributed to an overall improvement in code quality.  With a more comprehensive testing suite, the telecommunications team gained greater confidence in the stability and reliability of their software. This translates into a more robust network infrastructure for the telecommunications company and a potentially smoother user experience for their customers.

If you are aiming to achieve higher code coverage for better results, then Webomates can be your reliable solution. Contact us now at info@webomates.com or book a free demo for more details. 

Tags: Code Coverage, Code Coverage Criteria, Code Coverage in Software Testing, Software Testing