Introduction
Code Coverage is a very important part of the Software Development life cycle. It helps to ensure that tests are covering the most critical parts of our application, and is an important measure to determine the reliability of the code!
In this article, we'll explore what is Code Coverage, Its importance, How it works, and many more! So without delaying further, let's get started!
What is Code Coverage?
Code coverage measures the percentage of code that is tested. It's a very useful metric to test the quality of the test suite and is one of the major forms of White Box Testing.
A program with high test coverage is more likely to have fewer bugs compared to a program with low test coverage
The Formula of Code Coverage:
Code Coverage Percentage = (Number of lines of code executed)/(Total Number of lines of code in an application) \ 100.*
Why Code Coverage Matters?
Ok, now that you’ve understood what code coverage is, let’s know why should we care about Code Coverage? What will we get from it?
In this section, we will explore the importance of Code Coverage:
It helps us to find the untested code where the potential can be. So by finding them, we can minimize the chances of getting bugs.
It helps detect regressions early. By tracking code coverage over time, any drop in coverage can indicate a regression that requires further testing.
By detecting the unused it helps to improve the maintainability.
It seamlessly integrates with CI/CD pipelines, automating coverage measurement throughout the development lifecycle.
It works with a variety of programming languages and platforms like C#, Java, JavaScript, and more. This allows the testing of heterogeneous systems
How Code Coverage Works?
There are many approaches to measure Code Coverage but overall there are three main ways to measure it.
Instrumentation - The code coverage tool modifies the source code by inserting tracing calls. This allows it to track the executed parts of the code.
Test Execution - The test suite is run against the instrumented code. The tracing calls collect data on which lines, functions, branches, etc. were executed.
Reporting - The code coverage tool analyzes the collected data and generates a report showing the percentage of various coverage criteria that were met.
What are the Levels of Code Coverage?
Several levels of code coverage can be measured to determine how thoroughly your test suite exercises your code:
Statement coverage - This measures the percentage of statements in your source code that have been executed by tests. Simply counting the number of lines executed gives you the statement coverage.
Branch coverage - This measures the percentage of branches in your source code that have been executed. Branches refer to decision points like if-else statements, loops, etc. To achieve full branch coverage, tests must execute every branch at least once.
Condition coverage - This measures the percentage of conditions within branches that have been tested for both true and false. It focuses on individual Boolean expressions rather than full branches.
Path coverage - This measures the percentage of possible paths through your program that have been executed. It takes into account the order of execution and all possible paths through the code.
Modified condition/decision coverage (MC/DC) - This is the strongest form of coverage and requires that each condition independently affects a decision outcome. To achieve MC/DC coverage, tests must vary one condition at a time while holding others constant.
What are the tools used for determining Code Coverage?
There are several tools available in the market to measure the Code Coverage of any Software. Some are given below:
Cobertura:- Cobertura is an open-source code coverage tool for Java programs. It provides line and branch coverage reports, highlighting untested code and helping developers improve their test suites.
Keploy : – Keploy is an open-source testing tool that has inbuilt capabilities to provide the code coverage. It provides detailed reports with line, branch, statement and branch metrics, and also the way to improve test suites to get higher code coverage.
Gretel :- Gretel is a lightweight code coverage tool for Python. It provides statement and branch coverage metrics, helping developers ensure that their Python code is thoroughly tested.
Kalistick :- Kalistick is a cloud-based code coverage and quality analysis tool. It supports multiple languages and provides detailed reports on coverage, complexity, and other quality metrics.
JaCoCo: – JaCoCo (Java Code Coverage) is an open-source tool that provides comprehensive code coverage reports for Java applications. It integrates with popular build tools like Maven and Gradle, making it easy to incorporate into the development workflow.
OpenCover :- OpenCover is an open-source code coverage tool for .NET applications. It provides statement and branch coverage metrics, integrating with CI/CD tools like Jenkins and Azure DevOps.
Emma : – Emma is an open-source code coverage tool for Java. It provides fast and accurate coverage reports, highlighting untested code and helping developers improve their test suites.
GCT : – GCT is a code coverage tool for C and C++ programs. It provides detailed coverage reports, helping developers ensure that their code is thoroughly tested and free of bugs.
Conclusion
Hence, Code coverage is an indispensable part of the software development lifecycle, providing crucial insights into the effectiveness of test suites and helping to ensure high-quality, reliable software. By measuring the percentage of code that is tested, developers can identify untested areas, detect regressions early, and improve maintainability.
Various tools are available to measure code coverage, each offering unique features and capabilities to suit different development environments and programming languages. By integrating code coverage tools into CI/CD pipelines, teams can automate the measurement and reporting of coverage metrics, maintaining high standards of code quality throughout the development process.
Thank you for Reading :)
Frequently Asked Questions (FAQs)
How can Code Coverage be integrated into the CI/CD pipeline?
Code Coverage tools can seamlessly integrate into CI/CD pipelines, automating the measurement and reporting of coverage metrics. By incorporating tools like JaCoCo, Keploy, or OpenCover into your CI/CD setup, you can ensure that code coverage is consistently tracked with each build and deployment. This integration helps detect regressions early, maintain high code quality, and ensure that new code changes are adequately tested before being released into production.
What is Code Coverage and why is it important in software development?
Code Coverage is a metric that measures the percentage of source code executed by a test suite. It is crucial because it helps identify untested areas of the code, reduces the risk of bugs, detects regressions early, and improves maintainability. High code coverage generally indicates a well-tested and robust application, leading to fewer issues in production.
How does Code Coverage work in practice?
Code Coverage works through three main steps: instrumentation, test execution, and reporting. The code is instrumented by inserting tracing calls to track execution, then the tests are run, and finally, a report is generated showing the percentage of statements, branches, conditions, and paths covered. This process helps developers understand which parts of the code are thoroughly tested and which are not.