Code Coverage vs Test Coverage - A Detailed Guide

Software testing is a crucial and indispensable step in the software development life cycle. It ensures the creation of high-performing software that can attract and retain customers. Software that undergoes thorough testing processes has fewer defects, performs better, and results in higher user satisfaction. To ensure effective and efficient software testing processes, good test case management practices can go a long way. One such practice is the use of a test management tool like Testworthy, that can aid in streamlining your team’s software testing efforts through one comprehensive platform.

When considering software testing, code coverage testing and test coverage are two main types of software testing techniques that are often encountered. These metrics are used to measure code quality and the depth and extent of testing. Although these terms are often used interchangeably and confused with one another, in reality, they stand for two entirely different concepts.

Code coverage refers to the code that is run and tested by a test suite whereas test coverage refers to how comprehensively those tests cover and test actual features and functions. Hence, code coverage is a quantitative measurement whereas test coverage is more focused on the qualitative aspect of the software product. However, both software testing techniques are used to ensure high quality code that result in optimum software solutions. Test case management and use of test management tools can help simplify execution of code coverage testing and test coverage techniques.

Let us look at the concepts in more detail.

Code Coverage

Simply put, code coverage refers to how much code is executed and covered with your test cases. 100% code coverage means all lines of the code have been run at least once during the software testing phase.

Code coverage testing ensures that the code written is defect-free and up to quality standards. By running all the code lines during software testing, any issues in syntax or bugs in the code can easily be found, identified, and fixed before they turn into bigger problems. Code coverage testing techniques can also help you uncover areas in the software which are not being covered by tests at all, hence helping you identify vulnerable areas of your code.

It is important to remember that even a 100 percent code coverage still does not ensure a high-quality software experience, because code coverage alone does not guarantee functionality. You may have tests that run the entire code but still fail to cover critical functionalities. Or you may have a mistake in the code that allows the code to run smoothly but gives the wrong results. For example, when writing a calculation, a developer might accidentally replace an addition function with a subtraction one. When code is tested, it will operate smoothly but the end results will not be what the customer wanted. Hence code coverage testing can identify issues within written code but cannot describe final user experience.

There are several open-source and commercial tools in the market that can help you assess your code coverage and learn which statements or code lines were run during your tests. These tools can run code coverage testing based on different techniques. Some of the most common software testing techniques in code coverage testing include:

  • Function coverage: How many of the defined functions have been run.

  • Branch coverage: Every branch i.e., every decision outcome, is executed and tested.

  • Condition coverage: Every condition must be evaluated and covered for both true and false values.

  • Statement coverage: All lines/statements are executed at least once.

  • Achieving high code coverage does not need to be the ultimate goal. There is no use writing tests that cover every line of code if those tests are not beneficial, necessary or based on client requirements or user experience. Whereas a high coverage is good, 100 percent coverage is not necessary and in fact, its cost might outweigh the benefits. Hence, rather than achieving maximum coverage in quantitative terms, code coverage should have a practical logic behind it with an emphasis on critical elements and end user perspectives. This is to avoid bad software testing practices where the emphasis is on quantity over quality.

    software testing + code coverage + test coverage

    Test Coverage

    Whereas code coverage is a technical concept, test coverage is more centered around non-technical aspects of user experience. Test coverage is a black-box testing technique that makes sures that functionality of software is tested and requirements are fulfilled and covered by test cases i.e., everything that needs to be tested is done so. It refers to the test cases which are created and recorded in documents and how comprehensively they test requirements and features i.e., how well test cases cover functionality. Hence, test cases are written against requirements documents to help you test for critical areas and features.

    Before testing, it is important to have the right testing strategy in place. Simply testing everything does not bring high returns. It is important that your tests cover the critical areas and functionalities in the application. Measuring test coverage can help you manage and analyse your software testing technique and finetune it to better achieve results and meet requirements. This allows you to use resources efficiently, and save time and money while covering all crucial aspects of an application.

    Testing teams often aim for a higher percentage of test coverage. This allows teams to uncover errors earlier in the SDLC, making it easier to roll back changes, save costs and prevent defects from reaching end users. High test coverage is important to verify important features and functions and ensure end-user satisfaction by providing a smooth user experience.

    Test Coverage Techniques

    Test coverage techniques can be divided into several types. These include:

    • Requirements coverage: Any development is redundant if it does not fulfil client needs and expectations. Requirements coverage ensures that your tests thoroughly go over and cover all the product requirements that are listed and/or needed by clients and end-users.

    • Boundary value coverage: This tests the boundary values of inputs i.e., upper and lower limits.

    • Risk coverage: This involves analysing the risks associated with a software product and business risks critical to the application and then testing accordingly to make sure all risks are covered and mitigated.

    • Compatibility coverage: This makes sure that the software works across different platforms, operating systems and browsers.

    • Features coverage: This involves tests to check that product features are working effectively, covering both expected results as well as unexpected deviations.

    To achieve good and effective coverage, it is important for the team to thoroughly understand product requirements and design a testing strategy accordingly. Existing testing procedures should be analyzed and modified according to specific needs. Testing should be prioritized and highly directed. Resources should be allocated smartly. Test automation, coupled with test case management best practices and a test management tool, can help you achieve higher test coverage.


    In summary, code coverage is about finding bugs and defects in written code whereas test coverage is about performance and features. Both aspects of software testing are important and need to be implemented together to ensure the creation of first-class products.

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