Code Coverage Vs Test Coverage

  • September 6, 2019
  • HibaSulaiman

To err is human – This is pretty much understandable with respect to coding and testing software applications. Although testers use numerous methodologies and follow coding standards, there are some defects in the apps which is why rigorous software testing is preferred. Automated testing is preferred but it can never eliminate the need for human intervention.  In the Agile and DevOps era, it is crucial to find a reliable mobile application testing company to test, measure and improve an app’s quality. Moving further, how do testers assess if all the features are covered in an app? Apparently there are two methods to do so, namely code coverage and test coverage. 

Now let’s have a look at how the two approaches are different and their contribution to software quality assurance:

Code Coverage:

Code coverage is a metric that is used to measure the number of lines covered by test cases. It lists down the following:

  • Total number of lines in code
  • Number of lines executed by tests

Both are co-related which means if the code coverage is high, the chances of undetected software defects are low. Code coverage is used to determine what proportion of a project’s code is being tested by coded tests. For instance, unit tests can be used to find out the code coverage feature of any software product. Tests should cover a large proportion of the code so as to avoid any bugs in the app. Code coverage is applicable to managed (Command Line Interface) and unmanaged (native) code. The various types of testing in code coverage include function coverage, branch coverage, condition, coverage, parameter value coverage, loop coverage, and statement coverage. It is a simple process that allows early bug detection and also emphasizes on improving the coverage. 

Test Coverage:

Test coverage determines if the test cases cover the entire functional requirements of a test. It is also known as the black-box testing, where test cases are written based on expected functionality. It simply refers to a set of test cases that are written against user requirements. Developers write documents that describe all the test cases and then these test groups may refer to whether the test cases are passed or failed. All such metrics used to check the functionality of an app fall under test coverage. Software developers test the code paths or carry out code coverage as part of unit tests. The most commonly used measures for test coverage measurement are unit testing, performance testing, functional testing, integration or system testing and acceptance testing. Test coverage tests all the features of software focusing on quality assurance. 

So now we know about both code coverage and test coverage, the underlying question is which one should a developer opt for? Well, coverage is important but works as a limited metric. Traditionally, verifying all testing areas is important, yet it is difficult to measure its functionality. QA teams lack clarity on the effectiveness of their testing efforts. Hence, it becomes important to use test coverage to focus on user expectations and requirements.


Ideally, both approaches can be used, but it is time-consuming so organizations need to choose one of the two processes. Code coverage can be a good choice, as it tells about all aspects of an application that are not being covered at all by any tests. QA teams can then, fill up these gaps by investigating the untested areas. Although test coverage can work perfectly fine too, as it emphasizes on achieving the user requirements, the scope of code coverage is comparatively high. So, I think it depends on QA teams whether they use code coverage or test coverage for quality assurance.