End-to-end Test Coverage: How Much Testing Is Enough?

How to know when you’ve done enough testing? Shouldn’t it be pretty easy to spot? Some say to stop testing once you stop finding bugs. Others will suggest stopping when all the tests have been executed and passed. As we finish testing or feel like it’s done, new test ideas can come up. Figuring out how much testing is enough testing is a challenging question in software development, as it depends on various factors, including the project’s goals, budget, timeline, complexity, and potential consequences of software failures. People often talk about achieving end-to-end test coverage. Once that’s done, then you’ll be suggested to stop testing. But what does that mean exactly?

What Is End-to-end Test Coverage?

End-to-end test coverage refers to a comprehensive testing approach in software development where the goal is to ensure that all aspects of a software application or system are thoroughly tested from a user’s perspective, from start to finish. This type of testing aims to verify that the entire system functions correctly and that all components and processes work seamlessly together.

Key characteristics and concepts of end-to-end test coverage include:

How To Know We’re Close to End-to-end Test Coverage?

With my experience as a junior tester, senior tester, and testing manager over 20 years, I have found a few ways where you can find out if the testing that is performed is enough or not.

1. All test ideas discussed in meetings, provided by managers, or tossed in between testing are implemented:  You went through each of the sample scenarios that came with the story to test. This means that you only executed the test cases created by someone else. This might feel like something is left, but often it is the case in teams with many seniors and junior testers. Junior testers are asked to remain within the scope of testing, hence they know when to stop when the list of testing is complete.
2. Testing time is over:  With all the SDLC, Agile, and other practices in place, testing is often a time-bound activity. As the race to market intensifies, someone can always declare that time is up and the software needs to be shipped. Like it or not, we have a finite amount of time for testing, so these may be good indicators that it’s time to stop. In such cases, testing is done based on the priority of test cases.
3. Testing has not produced desirable results:- It’s been months of repeating the same tests over and over again. Automation may have been implemented. If the management has stopped adding new features, the testing also need not be done as regressively as it was earlier. You know that even if there is a bug hidden, it would be a very simple error hence no point wasting resources on testing. We can stop.
4. Tired testers:- Whether it is towards the end of the day, or towards the end of product life, testers can feel exhausted and that is the time we should stop. If I cannot find a bug today after 5-6 hours of testing, I may lose focus because I am mentally tired. I may want to stop testing for today, and continue tomorrow. 
5.  Irrelevant Test ideas:- Sometimes the test ideas that we put in front of management can be dismissed and we hear that these tests are not worthy and the product can live with any bug related to those tests. In such cases, we can stop testing that particular functional area.

How to Know if You’re Almost Done with End-to-end Testing?

Apart from the general guidelines, there are several other situations that determine the extent and duration of software testing. After conducting a series of tests you might be satisfied with the quality of codes or the bug percentage but the reality might be a completely different picture. The quality and bugs percentage could be pointed in just the opposite direction. Releasing the software may prove expensive and detrimental to your business. You can control it by evaluating the possibility of finding more defects. 

This is inferred from the analysis of the results obtained so far. The analysis is important because:

• A newfound defect is a strong indication to continue testing as they often lead to other defects.
• If you found defects with a small portion of overall functionality, you should continue.
• If multiple testing of the functionality of the software does not showcase any defects, then it’s the right time to stop testing the software.
• Before putting a stop to software testing, you need to ensure that significant features are mostly or entirely tested for satisfactory performance.
• Always rely on comprehensive tests and results rather than base this decision on a false confidence veneer. It is not uncommon that many developers completely skip tests stating that as long as the codes comply; it has reached the acceptance testing benchmark.

Success comes from identifying risks early. The risk factors will determine your level of testing. If in various testing like Unit testing, System testing, or Regression testing, you’re getting positive results, then you can stop testing.

We can easily surmise that you can understand it’s time to stop software testing when you are confident of finding any additional defects and when various tests give you a high degree of confidence that the software is ready to be released.

Conclusion

There are no predefined rules that you can use to find how much testing is enough. Visualize project situations, project readiness, and timelines to decide on your own. In practice, the goal is to strike a balance between thorough testing and project constraints. Agile methodologies, for example, often emphasize continuous testing and iterative development, allowing for more flexibility in adapting testing efforts as the project progresses.

Ultimately, the decision of how much testing is enough should be a collaborative effort involving project stakeholders, including developers, testers, product owners, and project managers. It’s also essential to regularly reassess your testing strategy as the project evolves to ensure that you are effectively managing risk and delivering a quality product within the given constraints.