7 best practices for end-to-end (E2E) testing

End-to-end (E2E) testing surveys application workflows from start to finish to confirm overall functionality. Best practices for E2E testing include careful scope definition, the use of real-world scenarios, effective test writing, cross-functional collaboration and full usage of the powers of automation.

In many ways, out of all the different types of software testing available, E2E provides the most comprehensive testing method. It doesn’t merely cough out a limited “yes” or “no” answer (like some “black box” forms of testing) to the core question of “Does the application work as intended?”

E2E offers a more complete and nuanced answer to that core question by painting a richer portrait of application performance.

However, all this added perspective comes at a price. The very things that make E2E testing so comprehensive and valuable also make it slower and more cumbersome than other types of testing. It just takes more time for E2E testing to make its test results happen. At the same time, it takes more participation and patience on behalf of those overseeing the process.

That makes best practices for E2E testing even more important to follow. Through their implementation, you can help mitigate the outsized requirements of E2E testing that tend to slow down its use. Nor are concerns limited to speed, either. The best practices outlined here can increase the validity of the data produced by E2E testing, making the entire testing process more valuable in the end.

Before discussing the optimal ways to handle your E2E testing, let’s first make sure that this type of testing best suits your needs by reviewing its prime benefits. E2E fosters certain advantages, helping users:

• Detect bugs earlier: E2E testing helps flag and remediate debugging issues while still early in the software development process.

• Increase overall reliability: E2E testing generates needed answers to the core questions of software quality and application performance.

• Reduce application risks: The E2E testing process helps alert you about potential points of failure and how to remediate them.

• Save time and money: By fixing bugs earlier in the software development lifecycle (SDLC), testers generate cost savings and time savings. (Analogy: By putting off an inevitable auto repair, your car’s brakes continue getting worse, eventually requiring a much more expensive repair to also replace your rotors.)

• Develop better UX: Businesses now fully recognize user experience (UX) as a pivotal part of software development. E2E testing is geared to UX issues, as it strives to validate workflows and how an application’s real users personally receive user interfaces (UIs).

• Confirm business functionality: Several key variables influence application performance. One of these variables is the functionality of whole business processes that undergird the application’s operation. E2E testing can ensure that the application behaves in accordance with the business operation standards that govern it.

• Release software freely: When testers successfully engage in E2E testing—the most comprehensive form of software testing that exists—it tends to instill added confidence into the software’s creators. They know they’re able to release new applications more safely, due to the thorough and constant testing that the software now receives.

It’s true that not every type of organization is ideally suited for E2E testing, but the industries listed here have proven that they certainly are.

Several of them deal with some of the most important and guarded information that exists today.

We can break down the best practices for E2E testing into seven general areas, each of which involves the coming together of several separate steps.

This first step is primarily conceptual and involves intensive test planning. Remember, E2E testing largely concerns user experience, and that’s the logical place to start this whole testing process.

Put yourself in the shoes of a potential user of this application and think from the user’s perspective. What do they expect to get from their user experience? Is there likely to exist a great deal of difference in what they anticipate from one user to another? Which are the most important user journeys and the most frequently chosen?

Asking such questions can help you find out user expectations and the normal functions and workflows that are going to be associated with this application.

First, designate which workflows are most essential. This step would include oft-used processes like login, checkout (for e-commerce applications) and key integrations. These processes play the biggest role in ensuring system stability, and they’re considered vital to operational integrity.

During this area of E2E testing, it’s good practice to contemplate worst-case user scenarios for this app. You need to predict where a systemic app failure might create the worst amount of impact and disruption for its users. Testers often use risk-based testing to help decide what new features can be added to the app to optimize performance and stave off potential problems.

Well, maybe “perfect” isn’t the right word. Perfection here might not be truly attainable. But you can create the best possible test cases, and that’s of prime importance because test cases serve as the coin of the realm concerning E2E testing. Test cases are the tool of implementation that makes E2E testing possible. As such, their proper design is crucial.

Using what you’ve figured out about user needs and requirements during Step 1, start developing test cases. Smart testers strive for thoroughness and try to capture every likely user interaction that might be encountered during normal application behavior.

Testers formulate the test scenarios that outline different use scenarios as they pertain to all related individual components—like the front end, back end, databases and application programming interfaces (APIs). When possible, more complex workflows should be more narrowly focused to make test cases easier to handle and run.

The management of test cases carries similar importance, which is crucial because you might be dealing with multiple test cases. To keep them all straight, it’s essential to implement careful management with all your test cases (and the test suites that hold them in an organized fashion).

This means making sure that test cases remain easily identifiable and confirming that their titles can be clearly understood. Likewise, any preconditions must be articulated. Test cases should outline the needed resources to run that test and the expected outcomes of that test.

This might sound like double-speak, but consider it for a moment. As important as Step 2 is, it’s a moot point without a safe and capable test environment to house that test case. The test environment must strongly mimic the production environment that the application is typically used in and needs to be superconducive to testing.

Therefore, the test environment should contain similar types of service configurations, database schemas and API keys used in API testing. Likewise, test environments should have all necessary components, be they hardware-oriented, software-based or network-related. If it’s in the production environment, it should also be included in the test environment.

Now, a word about the data you’re using in test cases. It’s easy to get this far in the testing process and think you’ve covered all contingencies. If you don’t incorporate test data that demonstrates stability and approximates what you might encounter in real-world conditions, it might not be the case.

To get high-quality data, you might be able to repurpose former production data, the sensitive data of which have been removed. Barring that, synthetically generated data that imitates data characteristics is another possibility.

Finally, when testing has been completed, use established teardown mechanisms so data can be gathered and analyzed, and retesting can start again with new setup measures.

Now that you’ve gone to the effort of developing valuable test cases, you want to be able to call upon them and put them to use repeatedly.

Enter automation, the transformative power to manage the routine running of multiple test cases, as delegated to any number of programmed frameworks.

Test automation proves especially handy during regression testing, when automation offers significant time savings and enhanced productivity over manual testing. E2E testing frameworks like Selenium can automate web applications, while frameworks like Appium are designed to streamline and automate the test execution of mobile apps.

There are also test automation tools (such as Katalon) that use low-code technology and AI-powered capabilities designed to offer simple testing and equally easy test maintenance.

To extend the power of an organization’s E2E testing, forward-thinking companies try to integrate test automation into continuous integration/constant delivery (CI/CD) pipelines. When such organizations make E2E testing a regular part of their processes, the dividends they receive include automatic execution of tests, more efficient testing and early detection of looming performance issues.

It would be comforting to think that E2E testing was strictly an isolated proposition, especially considering how involved and time-consuming it usually proves to be. But that wouldn’t jibe with this reality: Testers derive maximum benefit from E2E testing only when it becomes a regularly occurring process.

Tests and their related metrics need to be constantly monitored and reviewed to make sure that they remain relevant over time. Situations can change drastically and suddenly, and user behavior is subject to the same whims. Test cases that once held considerable utility can turn flaky and unable to perform with value. Such tests demand immediate attention so they’re not able to portray inaccurate test results or drive up associated maintenance costs.

The testing strategy that an organization follows needs to involve tracked processes. This method means that testers can figure out if test cases are remaining relevant and worthwhile, or if they need to be replaced with new test cases.

Admittedly, there are things that E2E testing can do that other forms of software testing can’t. These other options can include weighting in on the quality of the user experience that the application produces and evaluating an application’s entire performance, from start to finish.

But as valuable as E2E testing is, it shouldn’t be any organization’s entire testing strategy. Other tests also have value in their own ways, and you should run tests of other types.

Unit testing and integration testing are perfectly useful for handling many low-importance errors. And because they’re not as large in scope as E2E testing, they can usually be accomplished quickly and with fewer resources.

There’s another reason for using unit testing and integration testing. If you’re working with edge cases and exception testing (looking at cases that exhibit characteristics beyond normal operation), the approach can be different. In these cases, the testing processes of unit testing or integration testing are better suited than E2E testing.

We’ve spoken about how critically important it is that you cultivate regular E2E testing as part of normal application hygiene. Another key aspect of E2E testing is that it does not become the sole province of one staff member. The more team members that can be at least tangentially involved, the better for the overall health of the testing process.

So, you’re going to want to foster a sense of collaboration among team members, whether they work in development teams, QA or other business units. Part and parcel of this process is supporting enhanced communication so that all team members and other stakeholders are apprised about essential facts or developments related to test coverage.

By the same token, testers should document the test cases they develop, making careful notations about the nature of the particular test and the issues that are involved. Such transparency and clarity go a long way in furthering team goals regarding E2E testing.

It’s been said before (like in this article) but it bears repeating. To carry out effective E2E testing, you must keep remembering the target audience you’re serving.

Really try to get inside the head of the user. What do they expect from the application? In what ways might a user engage with this app? That’s up to you to figure out, and you need to retain that user mindset when developing test cases.

Further, it’s smart to test the app in various browsers to make sure that no matter what the browser, the application operates smoothly. This step is mandatory these days, when people use various browsers and operating experiences.

One primary goal of E2E testing is to confirm that apps work great no matter where or how they’re being used. E2E testing is both broad enough and comprehensive enough to perform the extensive and involved system testing required to assure cross-platform compatibility.

It takes some amazing execution to help pull off an error-free user experience. Fortunately, E2E testing is more than up to supporting that complicated task.