What is End-to-End (E2E) Testing?

Before you release your product into the market, it is extremely important to properly test whether it’s functioning as intended. To do that, software developers utilize a variety of testing techniques that verify the software’s integrity. To thoroughly check their software from start to finish, developers implement End-to-End testing, often simply called E2E testing – an elaborate technique that mimics end user experience.

TL;DR

• Comprehensive E2E Testing: E2E testing simulates real user behavior to validate the entire system’s functionality, ensuring software integrity from start to finish.
• Essential for Software Quality: E2E tests validate software components and interconnected systems, providing a holistic view that individual component tests cannot achieve.
• Risk Mitigation: Performing E2E tests reduces risks by ensuring stability, verifying dependencies, and validating backend systems before deployment.
• Automation-Friendly: E2E testing can be automated, especially within CI pipelines, providing continuous validation with each iteration and code update.

Check also:

• Web Test Recorder - Which One Is The Best?
• Top Free Test Automation Tools
• Complete Guide to Low Code Automation

What Is End-to-End Testing?

End-to-End testing is one of the most useful and informative techniques for test automation, providing valuable data about the inner workings of the program from the end-user perspective. With E2E testing, developers can thoroughly verify the behaviour of their software. During the test, you will be trying to replicate key user behaviour scenarios when using your software. The actual list of things to do varies, depending on the type of software you’re testing – but in all cases, it is rather extensive.

When performing a software testing method, like e2e web application testing you would start with opening your browser and navigating to the proper URL, and then proceeding to use the software as intended for the end-user.

If you're new to software automation, take a look at this beginner's guide to automation with step-by-step screenshots.

Similarly, in the case of a regular desktop application or mobile application, you would open the app just like a user would, checking out every bit of functionality that is intended for the users to work with. Keep in mind that during E2E testing you won’t need to check developer-specific aspects of the software, only the end-user perspective if it is important to you.

End-to-End Testing Goals

During an E2E test, your goal is to verify all of the dependencies and data integrity that directly or indirectly influence the reception of the software by the end-user. This usually includes any external services, as well as databases used by the software and metrics, as well as any other system dependencies.

E2E tests will ideally be performed in the production environment, but this isn’t always possible. The tests can, of course, be performed in an independent End-to-End testing environment, but you should make sure it is as close to the production environment as possible.

Within the SDLC process, E2E tests are performed in the Testing phase, which is situated after Coding and before Deployment.

Why is End-to-End Testing Important?

Is End-to-End testing necessary? It is true that more and more developers make sure to implement an E2E testing phase before the final deployment of their software. There are many benefits to E2E tests, but the most crucial ones are:

• The ability to verify software performance from the end-user perspective
• Testing verifies not only the software itself but also any interrelated sub systems, increasing test coverage
• Validation of back-end systems
• Immediate end-user-like feedback on test failing

While tests such as unit testing or integration testing are very useful (functional testing), allowing you to verify the working of each component and providing quick results, they don’t give you the whole picture. By not performing E2E tests, you won’t know how the experience of using your software will look like from the end-user perspective.

For example, individual component testing (integration tests) might show promising results and full functionality. However, when combined, something goes wrong and produces a bug. By only checking individual components, you wouldn’t be able to find out about the bug.

With a proper End-to-End test, you can verify whether everything works correctly together as it should.

Even integration testing doesn’t cover all of the system components of your software, and you might never know whether every aspect of your app clicks together.

End-to-End testing is also one of the few functional testing types that can be performed manually, as well as automated - which is done especially often in Continuous Integration. In such a scenario, a chosen set of tests can be run automatically each time a new iteration is uploaded to the testing server.

Benefits of End-to-end Testing

• Simulates the End-User Experience: E2E testing replicates how a user interacts with the software, providing a realistic evaluation of its performance and behavior.
• Verifies Key Aspects: It checks not only security and performance but also ensures that the software accurately collects and processes data as intended, covering the business logic thoroughly.
• Ensures Application Integration: E2E testing validates that all integrated components of the application work seamlessly together, ensuring a consistent and reliable user experience.
• Risk Mitigation: By verifying the software's readiness for deployment, E2E testing minimizes risks, providing stability and reliability—key factors for stakeholder approval.
• Supports Bug Detection and Scenario Testing: E2E testing identifies bugs and validates different user scenarios, ensuring comprehensive coverage and quality assurance.

End-to-End Testing Framework

Alright, so now you know what End-to-End testing is – but how to exactly implement it? There is a wide variety of checks and individual tests that must be covered by your end-to-end test planning, some of which include:

1. Establishing test requirements in the preparation phase (including software and hardware requirements)
2. Creating proper documentation
3. Deciding what type of test environment will be used (production environment or independent test environment)
4. Preparation of test cases and general E2E design
5. Tracking of data input and output
6. Test execution and evaluation

When executing E2E testing methods, developers usually follow an established E2E testing framework that guides you throughout the process, enumerating various tasks and responsibilities. The framework is relatively simple and consists of only three elements:

Check our guide on the best End-to-end Testing Tools and Frameworks.

Establish user functions

The User Functions relates to listing the features of your software, as well as all of its interconnected software systems. To properly measure and test software functionality, you need to first think about what you’re going to test. After you’re finished with listing user functions, remember to record everything relevant to each of them, including both the input and output data. Since E2E testing can be considered holistic, you also need to pay attention to all of the relations between every individual function – how they work together and whether there are any clashes.

Come up with specific conditions

Now that you have established the user functions you’re going to test, you need to think about the testing conditions. Try to come up with as many quantifiable indicators that can be measured for each of the functions. These can range from response time to consistency of data flow, to simple convenience of use. Remember – you’re trying to imagine yourself as an end-user, so try to keep track of anything that might be an issue for a non-developer.

Create individual test cases

Finally, before the E2E testing can commence, you need to prepare specific test cases for each of the conditions. At this point, you have prepared a list of user functions to test, as well as data conditions that will be measured during the test. Now, you need to create at least one test case for each of the conditions. By test cases, we mean user scenarios during which specific indicators will be able to be measured.

And by test case preparation status, we mean the precise location of the test instances being developed, as compared to intended test cases.

End-to-end test cases for your testing process

Congratulations, you’ve almost reached the end! At this point, you should pretty much be a walking fountain of knowledge about End-to-End tests. However, the raw theory is one thing, and implementing those types of tests for system testing in reality is another. To make the process a bit more digestible, consider this End-to-End testing example for a website with shopping functionality:

1. Go to the specified URL
2. Open a list of products
3. Check whether the information on the list correlates with specific product pages
4. Try to add the product to the cart and look for visible confirmation
5. Navigate to the cart and check whether the product has been successfully added
6. Double-check all of the relevant information (price, product info, etc.)
7. Proceed with the check-out and verify payment options integration

See how simple it is in the end? Now you can implement E2E testing methodology in your software to ensure better end-user reception, increase your product quality, and build a positive brand image.

This is just a high level example. If you would like to learn how to create a proper test case from start to end, please check out our article on test case creation. You will have a better understanding on how to design test cases for manual and automatic testing. Also check out our other topics in our testing guide.

BugBug as the truly user-friendly e2e testing tool

BugBug offers a comprehensive suite of features designed to streamline and enhance the end-to-end testing process for web applications. Here’s an overview of BugBug’s standout features:

No-Code Test Creation and Recording

BugBug allows users to create automated tests without the need for coding. With its intuitive test recorder, users can simply interact with their application in a browser, and BugBug captures each action, click, and input. This makes it easy for teams, including those with non-technical backgrounds, to build automated tests quickly and efficiently.

Assertions and Automatic Selector Generation

While recording tests, BugBug enables users to add assertions directly, verifying the presence and behavior of specific elements like buttons, text fields, and page content. Additionally, BugBug automatically generates selectors, eliminating the need for manual coding and ensuring that tests are precise and maintainable.

Edit & Rewind Feature

One of BugBug’s unique features is its 'Edit & Rewind' capability. This allows testers to modify and add new steps at any position in the test sequence without rerunning the entire test. It’s perfect for saving time when adjusting tests, especially for long and complex testing scenarios. Testers can simply jump to the step they want to modify, make the necessary changes, and resume execution seamlessly.

Unlimited Local and Affordable Cloud Testing

BugBug supports unlimited local test runs for free, providing a cost-effective solution for teams to test extensively without financial limitations. For cloud testing, BugBug offers a fixed-price model, allowing users to scale up their testing efforts with unlimited cloud test runs per day, ensuring that their application is monitored continuously without escalating costs.

CI/CD Integration

BugBug’s API and Command Line Interface (CLI) provide seamless integration with popular CI/CD pipelines like GitHub Actions, GitLab CI, Jenkins, Bitbucket, and more. This allows teams to automate regression tests as part of their build and deployment processes, ensuring that tests are run automatically with every code update, reducing manual intervention, and accelerating development cycles.

Summary

End-to-end testing is a type of testing that focuses on validating the whole system from start to finish rather then testing individual functionalities. It is often seen as a software testing methodology, but it is not the case. It may be a part of a methodology (i.e. Agile testing) but it is by definition a type of software testing.

Performing end-to-end testing covers an important task of checking data flows and focuses on testing if any functional gaps occur. This type of testing is necessary to verify if the software is ready for the next release cycle.

Happy (automated) testing!