What is End To End Testing?
Shreya Bose, Community Contributor - February 20, 2023
End-to-end testing is a fascinating technique as it is often used in agile and many other testing methodologies, but it is still not easy to understand. It is like unit and functional testing, but your tests go beyond individual units. In the following sections, let’s explore end to end testing, a software testing technique that tests an application’s workflow from beginning to end in real user scenarios.
End-to-end testing is a type of testing that verifies the entire software application from start to finish, including all the systems, components, and integrations involved in the application’s workflow. It aims to ensure that the application functions correctly and meets the user requirements. E2E testing may involve various types of testing, such as GUI testing, integration testing, database testing, performance testing, security testing, and usability testing. Automated testing tools like Selenium, Cypress, and Appium are commonly used for E2E testing to improve efficiency and accuracy.
What is End to End Testing?
End-to-end testing (E2E testing) is a testing method that evaluates the entire application flow, from start to finish. It ensures that all components work as expected and the software application functions correctly in real-world scenarios.
In E2E testing, the software is tested from the end user’s perspective, simulating a real user scenario, including the user interface, backend services, databases, and network communication. The purpose of E2E testing is to validate the application’s overall behavior, including its functionality, reliability, performance, and security.
End-to-end testing aims to identify any defects or issues that may arise when different parts of the application interact with each other. By testing the entire system, end-to-end testing ensures that all components work together seamlessly to meet the user’s expectations. E2E testing is usually performed after integration testing, which tests individual modules, and before user acceptance testing, which ensures that the application meets the user’s requirements.
Benefits of End to End Testing
- Improved quality assurance: End-to-end testing can help ensure that all parts of a software application are working together correctly and that the application is meeting its intended business requirements.
- Increased confidence in the software: End-to-end testing can help increase the confidence that the software will function as expected in the real-world scenarios, giving assurance to stakeholders that the application is reliable and stable.
- Faster detection of defects: End-to-end testing can help detect defects early in the development cycle, allowing developers to fix the issues before they become more difficult and costly to resolve.
- Reduced costs: End-to-end testing can help reduce the costs associated with defects and bugs detected late in the development cycle or after the application has been deployed.
- Better alignment with business requirements: End-to-end testing can help ensure that the application meets the business requirements, making it more likely that the application will be accepted by its intended users.
- More efficient testing process: End-to-end testing can help streamline the testing process by testing the application from a user’s perspective, rather than testing individual components in isolation, making it easier to identify and address issues that may arise.
Overall, end-to-end testing is an essential practice for ensuring the quality, reliability, and usability of software applications.
Steps to Perform End to End Testing
The steps below are required to initiate and complete any E2E test.
- Analyze requirements. Have a clear idea of how the app is supposed to work in every aspect.
- Set up a test environment in alignment with all the requirements
- Analyze software and hardware requirements
- List down how every system needs to respond
- List down testing methods required to test these responses. Include clear descriptions of standards (language, tools, etc.) to be followed in each test.
- Design test cases
- Run tests, study, and save results
End to End Testing Example
Let’s say testers have to verify the functioning of a Gmail account. The following features have to be tested:
- Type the URL into the address bar to launch the Gmail login page.
- Log into the account with valid credentials.
- Access Inbox. Open Read and Unread emails.
- Compose a new email.
- Reply to and forward an existing email.
- Open the Sent items folder. Check emails there.
- Open the Spam folder. Check emails there.
- Log out of Gmail by clicking ‘logout’.
Three Types of Activities in E2E Testing
1. User Functions
To build user functions, do the following:
- List the features of the software and its interconnected sub-systems.
- For each function, track and record all actions performed. Do the same for all input and output data.
- Identify all relations between user functions.
- Establish if each user function is independent or reusable.
To build conditions based on user functions, decide a set of conditions for every user function. This could include timing, data conditions, etc., factors affecting user functions.
3. Test Cases
To build test cases for E2E Testing, keep the following in mind:
- Create multiple test cases to test every functionality of user functions.
- Assign at least a single, separate test case to every condition.
Follow-Up Read: Test Case Reduction and Techniques to Follow
How to measure End to End Testing
Consider the following factors to track the progress of end to end tests
- Test Case preparation: Are the right test cases being created to test every software feature? The graph representing this should show the rate at which current vs. planned test cases are being crafted.
- Weekly test: A percentage base report of test completion each week is essential. The important parameters here are currently executed, not executed, and failed test cases.
- Defect Details: A percentage of defects identified, closed, or opened each week is essential. Distributing defects (for resolution) based on priority helps testers and managers keep track of bugs and supervise their resolution.
- Test environment availability: This compares the amount of time scheduled for testing every day vs the time actually spent.
Main Challenges in End to End Testing
Naturally, detecting bugs in a complex workflow entails challenges. The two major ones are explained below:
- Creating workflows: To examine an app’s workflow, test cases in an E2E test suite must be run in a particular sequence. This sequence must match the path of the end-user as they navigate through the app. Creating test suites to match this workflow can be taxing, especially since they usually involve creating and running thousands of tests.
- Accessing Test Environment: It is easy to test apps in dev environments. However, every application has to be tested in client or production environments. Chances are that prod environments are not always available for testing. Testers must install local agents and log into virtual machines even when they are. Testers must also prepare for and prevent issues like system updates that might interrupt test execution. The best way to access an ideal test environment is to test on a real device cloud.
If in-house devices labs are not an option, use a service like BrowserStack that offers a cloud Selenium grid of 3000+ real devices and browsers for testing purposes. Access a device users will use to navigate an app and ensure that the app functions flawlessly in real user conditions.
Why do you need End to End Testing?
Every application is connected to and integrated with multiple systems and databases outside its environment. This makes the app’s workflow reasonably complicated. End to end testing in software testing determines if various dependencies of an application are working accurately. It also checks if accurate information is being communicated between multiple system components.
- Backend: E2E testing verifies the database and backend layers of an app. This is necessary since the app’s core functionalities depend on backend capabilities.
- Multi-tier system: If an application has a complex architecture whose workflow works through multiple tiers, E2E testing is necessary to verify overall functions and the interaction between individual tiers in the architecture.
- Distributed Environment: If an application is based on SOA (service-oriented architecture) or cloud environments, E2E testing is necessary. It is also necessary for apps to consist of multiple components that must work together for successful operation.
- Consistent User Experience: Since E2E testing involves the frontend, it also ensures that the app provides a user experience that works across multiple devices, platforms, and environments. Cross browser compatibility testing, for example, is an integral part of E2E testing in this regard.
Learn More: Front-End Testing Strategy
Best Practices for End to End Testing
To test end to end, it is crucial to follow the practices outlined below to ensure smooth testing and feasible cost management.
Prioritize the End Use
- When creating test cases, test like the user. Get into the mindset of someone using the app for the first time.
- Is it easy to find all the options? Are the features marked? Can users get what they want in two or three steps?
- Use acceptance testing documents and user stories that help clarify the user’s point of view. Design test cases accordingly.
- Focus E2E tests on app features whose failure will cause maximum issues. Start with these features, and design more elaborate test cases to verify them.
- Consider using a risk assessment matrix for this purpose.
Follow-Up Read: What is risk-based testing in agile?
Avoid Exception Testing
E2E Testing is best used to test common user scenarios. Regarding exceptional user scenarios, use integration testing or low-level unit testing.
- Since E2E testing encompasses the entire application, test cases are bound to be complex.
- Each system component has to be tested, which increases points of failure and also the difficulty in debugging each anomaly.
- Structure and organization are crucial in E2E testing.
- Conduct unit and integration tests initially to resolve the first level of errors.
Optimize setup and teardown mechanisms
- Ensure that the test environment is ready to start testing at any moment.
- Setup processes need to be as minimal as possible.
- Once tests are complete, it should take an equally low amount of time to erase the test data so that the environment reverts to a pristine state – thus ready to conduct tests again.
Given the importance of end-to-end testing, it needs to be planned from the very beginning of a project. Note that end-to-end testing is best conducted manually since it allows testers to put themselves in the users’ shoes. However, if automation testing is required, it is best to limit it to low-risk features that simply require repetitive action (For eg., filling in a signup form).
Start viewing end-to-end testing as a non-negotiable part of the testing pipeline. Prepare for it from the earliest stages, and invest time, effort, and resources in it so that the user does not have to deal with preventable disruption in their experience.
Frequently Asked Questions
1. What is E2E vs UAT testing?
E2E testing focuses on testing the application’s components and systems, while UAT focuses on testing the application’s usability and suitability for end-users. E2E testing is typically performed before UAT, to ensure that the application is functioning correctly, while UAT is performed after E2E testing to ensure that the application meets the end-users needs and expectations.
2. Which tool is used for end to end testing?
You can use tools like Selenium, BrowserStack, Cypress, and Appium, to perform end to end testing. When choosing an end to end testing tool, you should look for test coverage, ease of use, compatibility, and scalability.
3. What are the types of end to end testing?
There are two types or ways to perform end to end testing: horizontal and vertical. Both horizontal and vertical end-to-end testing achieve the same goal but have different advantages and prerequisites that may make one type more suitable for certain teams than the other.
Horizontal end-to-end testing is the most commonly used type and involves testing across multiple applications to verify each workflow or transaction from start to finish, ensuring that each process occurs correctly. This type of testing can occur within a single application or interface, but often involves external applications from third-party vendors or those developed internally.
On the other hand, vertical end-to-end testing entails testing each layer of a single application’s architecture from top to bottom. This means working through each sub-system independently from granular-level unit tests to tests at the UI and API layers.
4. Is E2E testing same as system testing?
End-to-end (E2E) testing and system testing are not the same, but they are related. End-to-end testing and System testing aim to ensure that the software application is working correctly; they have different scopes and focus areas. System testing is focused on verifying the software system as a whole, while E2E testing is focused on verifying the application’s workflow from start to finish.
System testing is a type of testing that verifies the entire system or software application is working correctly as a whole. This type of testing includes testing all the modules, components, and integrations of the software system to ensure that they are working together correctly. The focus of system testing is to check the system’s behavior as a whole and verify that it meets the business requirements.
End-to-end testing, on the other hand, is a type of testing that verifies the entire software application from start to finish, including all the systems, components, and integrations involved in the application’s workflow. The focus of E2E testing is on the business processes and user scenarios to ensure that they are working correctly and meet the user requirements.