End-to-end testing, also known as E2E testing, is a technique used to test an application’s workflow from start to finish in real-world user scenarios. One can run end-to-end tests using both manual and automation testing approaches. It is similar to unit and functional testing, but it goes beyond testing individual units and focuses on the entire application as a whole.
E2E testing is often used in agile development methodologies, as it helps to ensure that the application is working as expected and meets the requirements of the users. While E2E testing can be challenging to understand, it is an important technique for ensuring the quality and reliability of software applications.
In the following sections, we will explore E2E testing in more detail and look at some of the tools and techniques that can be used to perform E2E testing effectively.
Types of E2E testing activities
There are three types of activities involved in end-to-end testing: user functions, conditions, and test cases.
User functions are the features and interconnected subsystems of the software. To build user functions, the following steps can be taken:
- List the features of the software and its subsystems.
- Record all actions, inputs, and outputs for each function.
- Identify the relationships between user functions.
- Determine if each user function is independent or reusable
Conditions are factors that can affect user functions, such as timing and data conditions. To build conditions based on user functions, establish a set of conditions for each user function.
Test cases are used to test the functionality of user functions. To build test cases for end-to-end testing:
- Create multiple test cases to test each functionality of user functions.
- Assign at least one separate test case to each condition.
How to Measure E2E Testing?
There are several factors to consider when tracking the progress of end-to-end tests:
- Test case preparation: It is important to ensure that the right test cases are being created to test every software feature. A graph showing the current versus planned number of test cases can help track this.
- Weekly testing: A weekly report on the percentage of test completion can provide insight into the progress of testing. This report should include the number of executed, not executed, and failed test cases.
- Defect details: It is important to track the number of defects identified, closed, and opened each week. Distributing defects by priority can help testers and managers focus on the most critical issues.
- Test environment availability: It is important to ensure that there is enough time allocated for testing each day. A comparison of scheduled testing time versus actual testing time can help track this.
Why Is E2E Testing Important?
End-to-end testing is a form of software testing that evaluates the overall functionality of an application from beginning to end. This includes checking the performance of all components and systems that the application interacts with, such as external databases and systems.
End-to-end testing helps ensure that the various dependencies of the application are functioning correctly and that accurate communication is occurring between different system components. This type of testing is especially important for applications with complex workflows that rely on integration with multiple external systems and databases.
- Verifies the overall functionality of the application:
End-to-end testing helps ensure that the application is working correctly from start to finish, covering all components and systems that it interacts with. The goal of end-to-end testing is to identify any gaps, errors, or missing functionality in the system under test by simulating real-world scenarios.
End-to-end testing is typically performed after unit and integration testing, and it helps to ensure that the application is working correctly from start to finish.
- Catches and fixes issues early:
By performing end-to-end testing, developers and QA teams can catch and fix any issues or bugs that may arise when different components and systems are integrated and used together. This helps prevent issues from reaching the production environment and affecting users.
Performing end-to-end testing helps ensure that the application is working as intended and that all components are working together seamlessly. This is especially important for applications that have a lot of integration points, such as microservices or distributed systems, where there are many different components that need to work together to provide the desired functionality.
By catching and fixing issues early in the development process, end-to-end testing can help prevent problems from reaching the production environment and affecting users.
- Ensures reliability and performance:
By verifying the functionality of the application and its dependencies, end-to-end testing helps ensure that the application is reliable and performs as expected for users.
It is a way to ensure that the application is reliable and performs as expected for users. This type of testing is typically done by simulating user actions and verifying that the expected results occur. For example, if you have an e-commerce application, you might do end-to-end testing by adding items to a shopping cart, proceeding to checkout, and verifying that the correct order total is displayed and that the order is successfully placed.
End-to-end testing can help identify any issues that might arise during the use of the application, such as problems with the user interface, integration with other systems, or performance issues.
- Provides a consistent user experience:
End-to-end testing can also help ensure that the application provides a consistent user experience across different devices, platforms, and environments.
It’s important to test the application in a variety of different configurations to ensure that it works correctly for all users, regardless of the device or platform they are using. For example, if you have a web application, you might do end-to-end testing on different web browsers and operating systems to ensure that the application behaves consistently across different environments.
Similarly, if you have a mobile application, you might do end-to-end testing on different devices and operating systems to ensure that the application performs as expected on all of them.
By verifying the functionality of the application across different devices and environments, end-to-end testing helps ensure that users have a consistent and positive experience with the application.
LambdaTest can be used to automate E2E testing by providing a platform that allows you to run your tests across a wide range of devices and browsers. It provides a comprehensive testing environment for tools such as Selenium, Cypress, Playwright, and Puppeteer, enabling users to conduct end-to-end testing on over 3,000 browser and OS combinations.
This can help you catch any issues that may arise when your application is used on different platforms, ensuring that your application is fully functional and ready for deployment.
- Validates the integration of different components:
End-to-end testing verifies the integration of different components and systems, helping to ensure that they are working together correctly.
When building an application, it’s common to use a variety of different technologies and systems, such as databases, servers, and third-party APIs. End-to-end testing helps ensure that these different components are properly integrated and working together as expected.
For example, if you have an application that stores data in a database and retrieves it through an API, end-to-end testing can help verify that the data is being correctly stored and retrieved.
By testing the integration of different components and systems, end-to-end testing helps ensure that the application is reliable and performs as expected for users.
- Identifies issues with dependencies:
End-to-end testing can identify issues with dependencies, such as external systems or databases, that may not be uncovered by other types of testing.
Dependencies are an important part of many applications, and it’s important to ensure that they are functioning correctly. End-to-end testing can help identify any issues with dependencies by simulating the use of the application and verifying that the expected results occur.
For example, if you have an application that relies on an external API to retrieve data, end-to-end testing can help verify that the API is functioning correctly and that the data is being retrieved as expected.
By testing the dependencies of the application, end-to-end testing helps ensure that the application is reliable and performs as expected for users.
7. Verify the functions of multi-tier systems:
When an application has a multi-tiered architecture, it can be challenging to test all of the interactions between the different tiers using other types of testing, such as unit testing or integration testing. End-to-end testing is designed to test the application from start to finish, including all of its dependencies and interactions between different tiers.
This can help identify any issues that might arise during the use of the application, such as problems with the user interface, integration with other systems, or performance issues.
By verifying the overall functions and interactions between different tiers in the architecture, end-to-end testing helps ensure that the application is reliable and performs as expected for users.
8. Useful in distributed environments
End-to-end testing is especially important for applications that are based on a service-oriented architecture (SOA) or cloud environments, or that consist of multiple components that must work together for successful operation. In these types of environments, it’s important to ensure that the various components and services are functioning correctly and interacting as expected.
Challenges in End-to-End Testing
Here are a few more challenges that might be encountered:
- Complex dependencies: If the application has complex dependencies, such as multiple third-party APIs or systems that need to be integrated, it can be challenging to test all of the interactions between these dependencies. This can make it difficult to identify any issues that might arise during the use of the application.
- Flaky tests: End-to-end tests can be prone to flakiness, meaning that they sometimes fail for no apparent reason. This can be caused by a variety of factors, such as network issues, timing issues, or race conditions. Flaky tests can be frustrating to deal with and can make it difficult to identify the root cause of issues.
- Performance issues: If the application has performance issues, it can be challenging to identify the cause of the problem through end-to-end testing. This is because end-to-end tests generally run at a high level and don’t provide much visibility into the underlying systems and dependencies.
- Maintenance: End-to-end tests can be time-consuming to set up and maintain, especially if the application has a complex workflow or a lot of dependencies. It’s important to regularly update and maintain the end-to-end test suite to ensure that it’s effective at detecting issues.
LambdaTest is a cross-browser testing platform that allows developers and testers to overcome challenges related to testing applications on a variety of devices and platforms.
LambdaTest also offers features such as flaky test tracking and parallel testing to help improve the efficiency of the testing process.
End-to-end testing is a valuable tool for a range of professionals, including developers, testers, managers, and users. Developers can use end-to-end testing to offload much of the testing and quality assurance process to the QA team, allowing them to focus on building new features. Testers can easily write end-to-end tests by basing them on observed user behavior, which can be documented through usability testing.
This type of testing is effective at identifying problems before the software is released to end users, making it easier for managers to prioritize tasks in the development process. Overall, end-to-end testing helps ensure that the software meets the needs and expectations of real-world users.