What is End to End Testing? Ensuring Seamless Performance

End to End testing is a software testing approach used to test the system workflow from beginning to end. Learn about e2e testing in our latest guide.

End-to-end testing, also referred to as E2E testing, is a technique to test out the completeness of the software product from beginning to end from the users’ perspective. It ensures that all the software pieces work together.

The E2E testing process starts when the development has reached the stage that is known as the Minimum Viable Product (MVP). E2E testing also differs from integration, unit, and UI testing, and testers might cover slight overlaps in the ground during tests.

Why End-to-End Testing Matters

End to end testing process (E2E) should provide a satisfying experience for users. It ensures that the system behaves as expected in a real-world scenario and has a vital role in delivering high-quality software. Here are some key reasons why end-to-end testing is essential:

• Identifying System Bottlenecks
  • E2E testing helps uncover performance issues that may not be apparent in unit or integration tests.
  • Simulating real user interactions reveals slowdowns or inefficiencies in the system.
  • This proactive identification helps maintain a smooth and responsive user experience.
• Ensuring Integration Compatibility
  • Applications are typically composed of multiple components and services that need to work seamlessly together.
  • E2E testing verifies that these components integrate correctly, ensuring that changes in one part of the system do not cause unexpected issues in another.
• Enhancing User Satisfaction
  • By validating the entire user journey, E2E testing ensures that the application meets user expectations in terms of functionality and performance.
  • It helps in catching user interface and experience issues that might not be detected through other forms of testing.

End to end testing best practices, such as early automated testing, regular script updates, and a comprehensive testing strategy with realistic scenarios, ensure thorough software validation throughout development.

Types of E2E Testing

End to end testing encompasses various types of tests to cover the entire application workflow. Here are the main types of E2E testing:

• API Testing
  • Tests application programming interfaces (APIs) directly and in integration scenarios.
  • Verifies functionality, reliability, performance, and security.
  • Sends requests and validates responses without a graphical user interface (GUI).
  • Focuses on message layer communication and data handling.
• User Interface (UI) Testing
  • Ensures the system is making the correct API calls and receiving proper responses for functionality.
  • Often implicit within main system testing, but can be performed specifically.
  • Especially important when making changes to an API.
• Database Testing
  • Ensures that the database operations, such as CRUD (Create, Read, Update, Delete) actions, perform correctly.
  • Verifies data integrity and consistency by checking constraints, indexes, and triggers.
  • Validates that the data is stored, retrieved, and processed correctly within the database.
• Integration Testing
  • Verifies the correct functioning of external APIs used by web applications.
  • Ensures that integrations handle both expected and unexpected data properly.
  • Tests interactions between different components and services to identify any issues.
• System Testing
  • Tests the complete and integrated application to verify that it meets the specified requirements.
  • Involves evaluating the end-to-end functionalities of the application, including hardware and software environments.
  • Ensures that the system as a whole performs well under various conditions and scenarios.

Benefits of End-to-End Testing

Since end-to-end testing employs a full-stack testing methodology, there are several benefits that organizations can expect in terms of overall software quality, workflow optimization, and efficient operation.

First, end-to-end testing is responsible for uncovering issues and defects with the application that are not apparent in unit testing. Since end-to-end testing is carried out with the users’ perspective in mind, problems present in the application are highlighted. In contrast, unit testing only tests out single, isolated components. E2E testing also acts as a verification step for the software’s overall business logic and workflow.

Another significant benefit is increased efficiency in terms of time and costs. End-to-end testing can ensure that you do not need to run repeated tests, decreasing the time and costs spent on testing.

Finally, end-to-end testing is a great way to ensure that application dependencies work correctly and cohabit without issues, including any third-party codes. This has the effect of quickly and effectively increasing your test coverage, which increases confidence in the product before launch.

End-to-End Testing Challenges

Successfully carrying out end-to-end testing can be challenging. Here are some common challenges that come with E2E testing:

• Test Speed: Since end-to-end tests cover every component in the software and go through the entire software stack, tests can run slower than other testing techniques that only test isolated parts of the software. 
• Test Complexity: End-to-end testing is incredibly complex as the entire software stack, all dependencies, and mimicking actual user interactions are involved. Test cases that replicate real user scenarios can become unstable due to the complex nature of basic usage scenarios.
• Test Maintenance: The most crucial challenge with E2E testing is dealing with test maintenance demands. The extended test flows, the high number of test steps, and the need to keep up with many potential UI changes can make long-term maintenance a time-consuming and effort-heavy responsibility. 

How End-to-End Testing Works

Generally, end-to-end tests are designed to scope outbreaks in this flow, which would indicate an error.

Creating end-to-end tests involves planning and design of the tests according to the requirements of the software. Testers can use different testing platforms or frameworks for this purpose.

The tests are then executed, usually with the help of different devices. Any failed tests are then examined, and the relevant areas of the code are debugged. The tests are rerun multiple times if needed until they pass entirely.

Planning

In this stage, the team plans and specifies the resources for testing, the critical testing tasks to cover, and all relevant testing schedules.

Design

The test design phase is a crucial phase that involves creating test specifications, generating the appropriate test cases, carrying out usage and risk analysis, and finally, creating a test schedule.

Execution

The tests follow the plans and schedules in this phase, and testing results are appropriately documented.

Analysis

Finally, the test results are analyzed in detail. Depending on the analysis, the team can evaluate the success of the testing or carry out more tests if needed.

End-to-End Testing Methods

To design E2E testing, teams often use one of two approaches: the vertical and the horizontal methods.

Vertical Method

In the vertical method, testing typically occurs in layers. This involves creating a hierarchical order of importance, and the tests are then carried out in the order of the hierarchy sequence. Component-level testing is carried out to ensure optimum quality. This approach is less focused on the user experience and more involved with testing the parts of the software in detail.

Horizontal Method

This involves parallel testing of multiple software components simultaneously. In the same testing run, tests are carried out horizontally over numerous application components, usually with the help of an ERP solution.

End-to-End Testing Metrics to Use

E2E testing can make use of quite a few metrics, including:

• Defect Status – Expressed as a percentage or ratio of open vs. closed defects over a defined period. These are then arranged according to their priority and assessed based on severity and consequence.
• Progress Tracking – Tracking of test completion, expressed by a percentage, gathered over a defined period. Details of test completion can include data regarding complete and incomplete tests, passed or failed tests, executed or unexecuted tests, and valid or invalid test cases.
• Test Case Design –  This tracks the progress of the actual completion of test case preparation against the planned preparation rate.
• Environment Availability – This tracks the actual amount of operational testing hours over a while against the planned number of hours for testing.

End to End Testing Automation

As in most other areas of software testing, end-to-end testing can also benefit significantly from test automation. With that said, due to the complex nature of end-to-end tests, it can often be challenging to automate them successfully. This is one situation where choosing a capable, modern test automation tools can help.

You need a test automation platform resistant to fragile tests for an efficiently automated end-to-end testing workflow to ensure that tests are automatically healed and maintained. A platform that allows for easy and intuitive test creation and one that provides specific, detailed data.

How to Do End-to-End testing: Step-by-Step Instructions

A step-by-step breakdown of end-to-end testing involves identifying critical test scenarios, mapping each step, and creating the tests. Once this is done, you can automate and integrate the tests into your CI pipeline.

To identify test scenarios, consider actual use cases that need testing before release. This can be a group effort of brainstorming with the participation of testers, developers, and other stakeholders. 

With each scenario, you can map out the different steps and actions associated with them and the expected outcome.

These can then be converted into actual test cases. You can run them manually or proceed with automated testing. While not all tests can be automated, using the right test automation platform will allow you to automate most tests and extract maximum performance and efficiency.

Finally, you can add automated end-to-end tests to your CI pipeline. This will provide meaningful feedback to the development team and help standardize creating and running end-to-end tests.

‍End to End Testing Example

A typical instance of end to end testing example for ticketing system software for trains would involve:

1. Entering the software URL and logging in with valid user credentials.
2. Entering the source and destination locations of the journey, the date of the trip, and the class of travel
3. Selecting the preferred transport option,
4. Selecting the number of tickets,
5. Completing payment for the same using their preferred digital payment option
6. Getting a copy of the ticket on the screen with the option to get a printout and another copy automatically sent to the user’s email address.

E2E Testing Checklist

A checklist for E2E testing can look at the following:

• Test the software’s functionality, considering the expected workflow during user interaction.
• Test the software system’s performance to ensure a uniform, seamless user experience while navigating.
• Test the data storage of the software to ensure that data can be appropriately stored, organized, retrieved, and updated as and when necessary.
• Perform usability tests that ensure the degree of usability and ease of use of all the software system components as part of a typical user flow.
• Perform security and vulnerability testing.

End to end Testing vs Other Software Testing Methods 

Each testing method has a unique role in software development. End to end testing process offers a thorough evaluation of the application's behavior in real-world scenarios.

• End to End Testing vs Functional Testing
  • End to End Testing: tests the complete workflow of an application, from start to finish, ensuring that all components work together.
  • Functional Testing: aims to ensure that software operates as intended by checking if the application performs its specified functions correctly.
• End to End Testing vs Unit Testing
  • End to End Testing: covers the full application from start to finish.
  • Unit Testing: examines individual units or components of the application in isolation to verify their correctness.
• End to End Testing vs Integration Testing
  • End to End Testing: Ensures all parts work together as a whole from the user’s perspective.
  • Integration Testing: focuses on verifying the interaction between various modules or elements within a software application. 
• End to End Testing vs System Testing
  • End to End Testing: Simulates real user scenarios across the entire system.
  • System Testing: evaluate the complete system to meet specified requirements.
• End to End Testing vs Regression Testing
  • End to End Testing: ensures the application’s full workflow is intact after changes or updates.
  • Regression Testing: re-running functional and non-functional tests to ensure that previously developed and tested software still performs as expected after a change.

Conclusion

• End to end testing ensures the software behaves seamlessly in real-world scenarios, focusing on the complete user experience.
• Unlike other tests that are primarily technical and at the component level like regression testing, E2E testing verifies the entire workflow of the application.
• Organizations benefit from investing in E2E testing tools and resources to maintain high-quality user experiences consistently.
• End to end testing automation simplifies and accelerates the validation of software functionality across various scenarios and environments.