I’m sure most of us would agree we testers are paid to disbelieve in a product.
It’s not that easy being a software QA— even though we’re trying to give our best, chances are we tend to miss out few scenarios while testing. It’s only human to make mistakes – but being QA is a tough job, as we cannot afford to do the same.
Nowadays software development activities are more systematic and organized, and organizations are seeking measures of testing completeness and effectiveness to show test completion criteria. Of them all, code coverage is considered especially valuable.
So what is Test Coverage? It is nothing but “What are we testing and How much are we testing?”
It is very useful for finding untested parts of a codebase and helps monitor the quality of testing and assists the testers to create new tests that cover areas that are missing or not validated as part of their regular test cases, and this will gauge how well an application has been tested.
It is also important to know when to calculate the coverage. If you do this too early in the phase, you will see a lot of gaps because either the code is still incomplete or in progress. So, it is advised to wait until the Last Build i.e. Final Regression Build. This will provide an accurate coverage value of the Tests being performed for given set of requirements.
For a software code, we have three basic types of test coverage:
In Statement coverage, the test cases are executed in such a way that every statement of the code is executed at least once.
In Branch coverage, test cases are executed in such a way that each condition in a decision takes on all possible outcomes at least once, and each point of entry to a program or subroutine is invoked at least once.
In Basic path coverage, the test cases are executed in such a way that every path is executed at least once.
Over the years, several tools have been developed, both open source and commercial to serve the code coverage needs of any software project. Whether you’re a single developer working on a side project at home, or an enterprise with a large DevOps team, or working on QA, there’s a code coverage tool to suit every need. Code coverage tools are available for many programming languages such as Cobertura, CodeCover, EMMA, Bullseye etc.
The coverage tools will first instrument the application under test DLLs and exes. Instrumentation is a process of inserting additional code in to the compiled program for collecting the measurement data while the program is running.
Once the instrumentation process is completed, the code coverage tool will bring up the application under test. The next step is to execute all the different test cases on the application under test. While the user runs different test cases scenarios on the application in the background, the coverage tool will analyse the coverage of the application code. These test cases can be either be manual or an automated suite.
How do we adopt a proper Test Coverage method?
QA team must be aware of the scope of work that is involved so that test cases can be created and be reviewed. This way, the team would be aware if more tests needs to be added. To do this, one can make use of RTM as is the typical practice.
To accomplish the above, check resource assignment and test execution process to see if everything is tested in an more effective manner.
A table such as below can be helpful:
Key benefits of Testing Coverage awareness for a Tester:
- Primarily helps prioritizing with testing task
- Helps achieving 100% requirement coverage
- Impacts Analysis becomes easier
- Useful in determining the EXIT criteria
- Enables a test lead to prepare a clear test closure report
Test coverage doesn’t end with the mentioned above contexts. There are many other points that needs to be considered when it comes to testing coverage.
It is not always true that when you test more, the results are better. In fact, when you test more with no apparent strategy, you probably will end up investing a lot of time.
With a more structured approach, an aim at 100% requirement coverage and effective testing methods, you will not compromise on the quality of the product.
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