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 - E2E Testing

• 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.

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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. The 'testing pyramid' is a foundational concept in agile software development, with unit tests at the base, integration tests in the middle, and E2E tests at the top, highlighting the importance of E2E testing in validating the entire user journey.

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. Cross browser testing is crucial in this context to ensure that the application functions correctly across different browsers, providing a consistent and reliable user experience.

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. Using different test environments for integration and end-to-end testing is crucial to accurately simulate real-world scenarios and interactions with external applications.

Within the SDLC process, E2E tests are performed in the Testing phase, which is situated after Coding and before Deployment. Simulating real-world scenarios during E2E testing thoroughly validates user interactions and application behaviors, ensuring the overall user experience meets expectations and functions seamlessly in practical applications.

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

Integration testing verifies the correct interaction between individual software modules, complementing E2E testing by ensuring that each part works together seamlessly.

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.

E2E testing contributes significantly to overall software quality by identifying defects, ensuring that workflows are optimized, and validating business logic within the application.

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. This comprehensive approach enhances user satisfaction by ensuring the application performs well in real-world scenarios.
• 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. Additionally, it can simulate user interactions by automatically executing test cases across different systems, which is crucial for maintaining efficiency and accuracy.

How to Implement End to End Testing?

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

Integrating E2E testing early in the development process is crucial to ensure effective communication among components and enhance overall project success.

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:

Identifying critical test scenarios during E2E testing is vital, as it involves mapping each test step and creating corresponding tests based on actual use cases. Collaboration among testers, developers, and stakeholders is essential for brainstorming these scenarios, ultimately leading to improved testing processes through automation and integration into CI pipelines.

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. Understanding critical business processes is essential, as disruptions to these processes can directly affect outcomes like customer satisfaction and revenue. 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.

Functional tests play a crucial role in validating specific functionalities to ensure that each piece of code meets the acceptance criteria.

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.

E2E Testing with BugBug

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 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:

It is also crucial to conduct user acceptance testing (UAT) as the final validation phase before releasing the software. UAT helps identify any remaining issues from the end-to-end test, ensuring the application’s overall functionality is validated before it reaches the users.

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.

An automated testing tool like BugBug simplifies the E2E testing process by verifying software module interactions and reducing time-consuming tasks, thereby enhancing time-to-market.

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.

Integration tests ensure proper communication and data exchange between different software modules or components, verifying the interaction between various parts of an application.

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. Manual testing is essential for evaluating complex scenarios that require human judgment, ensuring thorough evaluations of customer-facing aspects of applications. 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.

Additionally, regression testing is crucial for maintaining software stability and reliability after issues are resolved, ensuring that new changes do not negatively affect existing functionalities.

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.

Collaboration with the development team is crucial in the testing process to ensure that test scenarios are effectively integrated and any failures are promptly addressed.

How to Run End-to-End Tests with BugBug?

With BugBug, you can simulate the full user journey from start to finish — for example, logging in, browsing items, and checking out.

A full guide on your first test in BugBug is available here.

Steps:

1. Log in and create a new test on bugbug.io

2. Click “Create new test”

3. Enter the URL of your web app where the journey begins

4. Click “Start recording”

5. Perform the complete end-to-end flow (e.g., login → select product → add to cart → checkout)

6. Click “Finish and close” in the overlay menu

Run the test to verify everything works from start to finish

Summary: End-to-End Testing Explained

End-to-end testing (E2E testing) is a test automation strategy that validates the entire system by simulating real user interactions across multiple components of an application—from the user interface to the database. This method ensures that real user scenarios work as expected and that critical user paths are functional.

Unlike other testing methods like unit or integration testing, E2E testing covers the entire application in a horizontal testing approach, ensuring every layer—from frontend to backend—is operating correctly together.

Key elements of E2E testing include functional testing, security testing, desktop testing, and database testing. To achieve success, teams need robust test planning, create detailed test cases, use powerful test automation tools, and regularly review test results to catch regressions early.

Successful E2E testing involves writing stable test scripts, continuously maintaining tests, and understanding how to maintain tests over time as the product evolves. Leading testing tools help automate real user interactions, ensuring the product aligns with user expectations.

✅ Action Points for Effective End-to-End Testing

1. Create a solid test plan
   – Focus on test planning that reflects real user scenarios and critical user paths.
2. Choose the right test automation tools
   – Select automation tools or end testing tools that support the entire application, including desktop testing and web platforms.
3. Write detailed test cases
   – Ensure detailed test cases cover the user interface, backend, and third-party services.
4. Automate functional and security testing
   – Integrate functional testing, security testing, and database testing into the E2E flow.
5. Focus on horizontal testing coverage
   – Test across multiple components to ensure the entire system works cohesively.
6. Maintain test scripts regularly
   – Continuously maintain tests and test scripts to adapt to app updates.
7. Involve testing in the development cycle
   – Involve testing teams early to align tests with user expectations.
8. Review test results regularly
   – Establish a routine to regularly review test results and update tests based on findings.
9. Compare end testing vs. other methods
   – Understand when to use end testing vs. unit, integration, or exploratory testing for maximum ROI.

Happy (automated) testing!