Improving Software Quality with Maximum Test Coverage

What is Test Coverage?

Test coverage is a metric and a quantitative approach in software testing that evaluates whether your test cases cover the application code and the amount of code covered while testing. Test coverage metrics helps you to enhance the testing process to maximize effectiveness and produce a quality software. Application software with more test coverage has lower chances of containing bugs and an application software with inadequate test coverage has higher chances of containing more bugs.

Code Coverage and Test Coverage

Code coverage and test coverage are frequently mistaken. Though the basic concepts are the same, there are slight differences. Code coverage refers to unit testing procedures that target all parts of the code at least once and are performed by developers.

Test coverage, on the other hand, ensures testing every requirement at least once and is the responsibility of the QA team.

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How to Attain More Test Coverage in Less Time? 

  • Testers must be aware of various requirements and functionalities to evaluate different tasks. Following the below helps maximize digital assurance service test coverage with less time and resources:
  • Always be aware of how a particular release differs from the previous release, as this will help you to identify various requirements more accurately and focus on maximum coverage.
  • Develop a testing strategy and consider all the application requirements and the testing methods. 
  • Interact with your project developers, scrum team, and business analyst groups to get more details about the new requirements.
  • Prioritize your requirements in the initial stage to focus your energy where it is most required.
  • The next step is to create a list of tasks for execution. It is essential to consider different types of testing, the type of applications developed and the team’s experience.
  • When time and resources are limited, it is essential to consider a risk-based testing approach. Consider the application’s critical areas with a high probability of errors.
  • Execute the most critical business test cases on all browsers and the rest of the test cases on a single browser to save time.
  • Keeping track of all the fixes, impacts, and versions of the product/project release is essential. 
  • A tester with complete knowledge of the application can give better test coverage. 
  • Always prioritize newly introduced requirements and existing functionalities (80:20 – 80% new test cases & 20% regression test cases). Regression testing should be conducted to ensure an impact on existing functionalities. 
  • Always use the updated regression test suite for execution (after every release, the regression suite should be updated with newly introduced requirements/defects). 
  • Identify the areas where we generally receive many defects and test these areas. 
  • Categorize regression test cases priority-wise as critical, high, medium & low. If we have a short testing duration, we always start testing high-priority test cases, followed by the remaining cases based on the available timeline.  

Test Coverage Metrics

Test Coverage = (Lines of code covered by tests / total lines of code) * 100

For example, if you have 10,000 lines of code:  

  • Your test cases should be able to test the entire codebase
  • If only 5,000 out of 10,000 lines of code are tested, the coverage is 50%

Benefits of Test Coverage

  • Finding areas of requirement that are not covered by the test suite
  • Creating additional test cases which will help increase coverage
  • Prioritizing testing tasks
  • Reducing time, scope, and cost
  • Achieving 100% requirement coverage
  • Preventing leakage of requirements
  • Easier impact analysis
  • Delivering defect-free product
  • Software quality gets improved

Drawbacks of Test Coverage Leakage

  • Possibility of bug leakage
  • Leaves certain areas untested
  • Impacts client business
  • Causes loss of reputation
  • Requires additional effort and time for testing and fixing defects

Delays ongoing release activities


The goal of test coverage varies based on the test execution level and the types of software being tested. Maximum test coverage can be accomplished by determining the ultimate scope of the requirement, achieving a solid grasp of the application, and prioritizing the test cases.

If the test coverage is sufficient, the number of defects will decrease, and the program quality will increase.