Fringe testing, often known as edge case testing, can reveal serious flaws.
During a regression testing cycle, your testers are likely to cover the majority of the intended application functionality and procedures. While they may not test every function exhaustively, they do comprehensively cover the happy path — what the user sees and the application uses to perform. When QA teams are short on time, regression testing can be reduced to evaluating simply the core functionality of a specific workflow sequence. If you simply test the primary user workflows, you will almost certainly miss numerous bugs prior to release.

Edge case testing, also known as fringe testing, evaluates how the application performs when you depart from the script. Fringe testing can involve testing out of order, bending the expected workflow, or uncovering features that the programme was not designed to execute. When you test edge cases, you use your imagination to get the programme to perform functions it was not designed to accomplish and then deduce the results.

The premise is straightforward: humans, on the whole, rarely follow rules. This is why edge case testing is necessary to validate deviations from the planned path. Because, without a doubt, people will depart from that route.

The edge test case scenarios are those that are possible but unknown or unintentional requirements features. When testers are dealing with particular and calculated value fields, boundary testing, in which testers validate between the extreme ends of a range of inputs, is an excellent technique to identify edge cases. However, testers discover edge case problems most frequently when performing end-to-end or system testing on the programme and its linked components. It’s similar to performing exploratory testing on the entire system, including all of its integrated components, such as the API connections, database, and messaging systems.

However, there is a disadvantage to testing for edge cases. Edge case testing is difficult and time consuming. Let’s look at how to identify, prioritise, and test edge cases in an application to ensure that coverage extends beyond the happy path.

How to look for edge cases

How does a quality assurance tester identify edge test cases or flaw in edge instances? The best advise is to seek for edge cases. In general, testers employ creativity and critical thinking to uncover edge case flaws during any test cycle – regression, functional, or at any time during the development cycle. Testers are constantly on the lookout for edge situations, or as many as they have time for — that is the fact. Once the application system is connected and sufficiently developed to do an end-to-end test, testers should budget time to locate those hidden, frequently obscure edge test cases.

An skilled QA tester can intuitively determine where an application is prone to fail, especially as they test a system for an extended period of time. Additionally, the more familiar they are with the client workflow, the better ready they are to identify edge circumstances.

Testers frequently discover typical edge situations in unexpected areas. Consider integration points at which the programme saves data to the database or processes data received via messages. How else are they going to discover edge cases? Consider what the customer expects the application to accomplish, and then consider how to fulfil the functions in an unexpected manner. More importantly, how can they use that function to get the application to run in an entirely new or unanticipated scenario?

For instance, suppose your application processes income tax returns for inhabitants of the United States, France, China, and the United Kingdom. Then there are four unique sets of tax rules and calculations, one for each country, plus additional rules for each state or region. Now, suppose you alter the US tax rules and successfully create a new country with a new set of rules, but using the existing dataset of customer accounts. You configure the system so that all user accounts pay dividends to your offshore bank account. While this is an extreme scenario, if the test is successful, you have discovered a severe security vulnerability.

Numerous edge test cases are trivial or insignificant. Continuing with our security-related scenario, suppose you’re testing the login process for a user who wishes to access their tax account. Consider yourself as a US client whose job it is to keep the tax rules current with any modifications. You are only authorised to see the United States account. You input a valid username but an invalid password. The system indicates an invalid login attempt. The following questions may help illustrate how to locate edge case problems in this example:

Can you double-click on the window’s frame to bypass the login?

Can you gain access without logging in if you click swiftly numerous times outside the login window or on the screen’s edge?

Do you have access as a system administrator or super user once you log in?

Do you now have access to all accounts if you’re logged in as an administrator?

Prioritizing edge cases

Once testers identify edge case flaws, they must assign them a priority for triage. Typically, an organisation prioritises edge case defects differently than it does regression testing cycle defects. In the preceding instances, we’ve been examining security and authentication — specifically, whatever way I can think of to circumvent them right within the UI. You may discover and test edge case issues throughout the application’s workflow. To prioritise edge case tests and defects properly, evaluate the frequency with which the issue is discovered, as well as the possible commercial impact on your firm and client.

Consider the preceding cases. If I am able to bypass the login process through the UI and acquire access to all accounts, this is a serious flaw that the company must address quickly. However, less severe edge test case faults may not be addressed immediately in the code, particularly if the product or development team does not anticipate anyone will take that path. This is why prioritising is critical – critical edge case defects must be addressed immediately, while minor problems can be delayed.

Due to their rarity or unexpected nature, edge test instances are difficult to defend. However, the company should analyse and prioritise edge cases as if they were a rare occurrence, rather than as a flaw that will arise at some point, depending on the user’s cunning. Perhaps they do not click around and deviate from the workflow. However, what if they do? Hackers spend a significant amount of effort testing for edge cases and exploiting vulnerabilities. They examine every component of a system that no one considers critical. If you want to maintain a customer’s faith in your application, edge case testing is critical.

Additionally, keep in mind that there may be edge cases at the device level. Due to the variety of Android versions, edge case faults may occur in one version but not in another. When prioritising edge situations, evaluate which devices your users own to determine whether fixing that defect is worth the effort. There are just too many device/OS combinations to handle all issues simultaneously, necessitating a prioritised approach.

In a nutshell, do not overlook edge case defects. Incorporate fringe testing into your entire quality assurance approach.

How to conduct edge case testing
Developing tests for edge cases is a natural extension of other types of testing. The distinction is that you must leave time for QA testers to exercise their creativity and imagination in order to conduct tests that deviate from the happy route. Prioritize the execution of edge case tests and incorporate them into your regression tests; alternatively, if time does not permit, assign a portion of the QA team to perform the tests post-regression. Wherever you test edge cases, they are a key component of a comprehensive QA testing strategy.

Testing for edge cases is challenging. The process of fringe testing needs time, consideration, innovation, and research. Bear in mind, however, that edge test cases illustrate how users exploit your application — whether intentionally or unintentionally — in order to obtain unwanted access to data and systems. It’s not only about security; assume an edge case fault in which scrolling without accidently touching a button is really difficult. This is not a case of evil intent; rather, it is a case of a terrible experience eroding client happiness and loyalty. Consider yourself as a customer or a hacker; this is the best way to find edge cases and problems. While edge case testing involves time, it is vital to the success of an application and your business that edge case tests are written and implemented.

If you are unable to test edge situations internally, you can hire a software testing partner you trust to execute this task swiftly and safely. Applause delivers software testing services and solutions that span the entire software development lifecycle, ensuring that enterprises provide excellent digital experiences. In terms of edge case testing, Applause’s global community of digital experts can help you identify faults within the scope you designate, on the devices you prioritise, and ensure that apps provide a secure, consistent user experience.

Finally, organisations test applications to ensure they deliver a high-quality experience to customers. To maintain confidence, testers must validate that an application is capable of performing both the usual workflow and all possible edge test cases that could cause the programme to malfunction or expose client data and systems. Testing edge cases is time well spent for the benefit of both the business and its customers.