Test Coverage Techniques Every Tester Must Know
By Neha Bharati, Community Contributor - May 11, 2022
Building software is helpful, but it is also prone to many errors. Software that has poor design doesn’t just ruin the user experience but also causes many functional problems along the way. The Consortium for Information & Software Quality (CISQ) report indicates that poor-quality software costs about $2.08 trillion in the US alone.
It is crucial to build useful products and test them using a solid testing strategy for good test coverage. It helps benchmark the health of a product. Different test coverage techniques help in developing a testing strategy. In this guide, you’ll learn about the different test coverage techniques that every tester must know.
What does Test Coverage mean?
Test coverage defines what percentage of application code is tested and whether the test cases cover all the code. It is calculated as
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 lines of code are tested out of 10,000, the coverage is 50%.
Test Coverage vs. Code Coverage
Code coverage is a metric related to unit testing. It measures the percentage of lines and execution paths in the code covered by at least one test case. It only measures how thoroughly the unit tests cover the existing code. Test coverage is a job for the QA developers and testers who measure how well an application is tested.
Read More: Test Coverage vs Code Coverage
Benefits of Test Coverage
Before learning about the different types of testing coverage techniques, let’s look at the benefits of testing your application early and defining your test coverage.
- Early Detection: It helps to detect any errors in your application at the initial stages of software development. Identifying gaps in the requirements and test cases can save a lot of time and effort in the future.
- Eliminate Redundancy: It is unnecessary to consider all test cases sometimes. Developers can identify such redundant cases and report them to make the code lighter.
- Fewer Resources: Better test coverage means fewer defects in production and user acceptance testing defects. This translates to fewer resources allocated for testing.
- Smoother Testing Cycles: Test coverage helps optimize regression tests, test case prioritization, test suite augmentation, and test suite minimization. All these, in turn, help in a smoother and more efficient software development life cycle.
Test Coverage Techniques
Test coverage techniques help you track the quality of your tests and cover the areas that are not validated yet. Some popular techniques are
- Product coverage which tells us how much of a product is covered
- Risk coverage informs us about the risks in an application
- Requirements coverage track how many of the requirements are met successfully
- Compatibility coverage checks the compatibility across multiple browsers and devices
Read More: How To Ensure Maximum Test Coverage
Product coverage tells us which parts of a product are tested. Say there is a counter that is to be tested. A counter is a simple application that can either increment or decrement a number, similar to adding items to a shopping cart. The operations of the counter have to be tested i.e. incrementing and decrementing the counter. But there may be other factors that need to be tested. For example, should the counter handle negative numbers?
Product coverage can be increased by prioritizing requirements, preparing a checklist of testing requirements, and implementing effective test automation to reduce testing times. Several cloud-based test automation tools like BrowserStack allow users to set up their website for testing in a few simple steps.
A product with good product coverage verifies every possible scenario like the ones described above.
This test coverage technique helps to assess the risks related to the application and tests them thoroughly.
The above image gives us an estimate of what must be tested and how critical it is. It shows the probability of something happening and the (negative) business impact it would have. Based on this, four zones have been defined:
- Very likely scenario with high impact – It must be tested
- Unlikely scenario with high impact – It should be tested
- Very likely scenario with low impact – It could be tested if there is time
- Unlikely scenario with low impact – the test is too expensive for the value it provides, so testing is not required
Say there is an application that depends on a third-party API. There is a risk here of the API going offline. Analyzing how the application should work in such a case is what risk coverage is all about.
If you want to say that your application is covered, all of its relevant risks should be listed and answer the questions they elicit.
Requirements coverage is the most basic and essential test coverage technique that helps assess if it meets the user’s requirements. It is simply a way of testing whether the required functionalities exist or not. If the software has promised certain deliveries, these promises must be met using this technique.
Device fragmentation is an exceptionally huge problem that many firms can run into because it can cause compatibility issues and hamper a product’s user experience. There are 9000+ devices, 8 browsers, and 21 operating systems available today. Testing across all combinations of device-browser-OS is a mammoth task. The compatibility test coverage technique ensures that the application is compatible across browsers and operating systems.
There are different categories of compatibility testing, such as:
- Browser Testing: Testing across browsers provides helpful information about how the application works across different browsers. BrowserStack Live provides 3000+ browsers and devices to test an application ensuring that you don’t miss out on your user’s preferred browser-device-OS combinations. Try for Free.
- Hardware Testing: The application is tested with different hardware configurations.
- Software compatibility: This involves testing the software with other software. An example would be testing Microsoft Word compatibility with Microsoft Outlook.
- Network testing: Assess the performance of an application in different network conditions like 3G,4G, and Wi-Fi.
- Mobile testing: It involves testing websites across different mobile devices and platforms like Android or iOS.
Making The Most Out Of Test Coverage Techniques
To build stable products, deciding on a test strategy is essential. A strong test strategy will help provide maximum test coverage for the code. The test strategy involves using the different test coverage techniques mentioned above. Although each technique has its own unique benefits, the QA team must decide and take the final call.
With proper test planning, they can understand the features, risks, compatibility issues, and product requirements. Nowadays, test strategy techniques use AI with self-correcting test cases that learn from previous executions and improve upon them, significantly reducing test maintenance.
It is not easy to define a strong testing strategy for any application. But if done well, it greatly benefits the business and reduces the team efforts in the long run. They help track the progress and quality of your testing and help the business catch defects early on and decide which tests to perform and which to avoid. These test coverage techniques cover the various aspects involved in testing a product and help build an overall concrete testing strategy.