A Comprehensive Guide to End to End (E2E) Testing

September 16, 2022

Software development involves a range of testing methods that ensure process’ success. Learn about end to end testing, which works on the whole system.

Software development involves a range of testing methods that ensure process’ success. Learn about end to end testing, which works on the whole system.

The software development process involves many different kinds of software testing methods, each with its own techniques and end goals. Some, such as integration tests and unit tests, deal with checking the working order of specific parts of the application.

Based on this, when your software is at or near completion, you need to test if it works properly from the perspective of the intended user experience. This, in a nutshell, is the goal of end-to-end testing.

What is End to End (E2E) Testing?

End to end testing, also referred to as E2E testing, is a technique to test out the entirety of the software product from beginning to end from the users’ perspective. It defines the system dependencies for the product and ensures that all the pieces work together.

The E2E testing process starts when the development has reached the stage that is commonly known as the Minimum Viable Product (MVP). E2E testing is also, by nature, different from integration testing, unit testing, and UI testing. There might be slight overlaps in the ground covered during tests.

Benefits of End-to-End Testing

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

First, it’s critical to note that end to end testing is often 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 as the central consideration, issues that manifest in the application as a whole are highlighted, while unit testing only tests out single components in isolation. Similarly, E2E testing also acts as a verification step for the overall business logic and workflow of the software.

Another important benefit is increased efficiency, especially when it comes to time and costs. End to end testing involves testing the software as a whole. This kind of thorough, full stack testing can ensure that you do not need to run repeated tests, or more tests than you absolutely need. This can lessen the overall time you dedicate to testing and also the costs involved. This can also spill over to other areas of software development as the time and costs you save can be allocated to other productive areas of the development process.

Finally, end to end testing, primarily due to its scope and approach, is a great way to ensure that application dependencies, including any third-party code that might have been used, all work correctly and cohabit without issues. This has the effect of quickly and effectively increasing your test coverage. Increased test coverage brings peace of mind and increases confidence in the product before launch.

End to End Testing Challenges

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

  • Test Pace – Since end-to-end tests cover every component in the software and go through the entire software stack, tests can be on the slow side, especially if you compare with other testing techniques that only test isolated components of the software. Slow tests can bring down the entire productivity in modern fast-paced development environments, and can be mitigated to a great degree by choosing the right testing platform and adopting the right E2E testing workflow.
  • Test Flakiness – End to end testing is incredibly complex as the entire software stack, all dependencies, and mimic actual user interactions. Test suites that replicate real-life user scenarios can, by nature, become unstable due to the complex nature of actual usage scenarios. Again, using the right testing framework that takes a modular approach can help.
  • Test Maintenance – The most important challenge with automated E2E testing is dealing with test maintenance demands. The long 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. A clearly defined test suite structure, an evolving testing strategy, and a testing framework that deals with test maintenance intuitively can help immensely.

How End to End Testing Works

Generally, end to end testing involves carrying out tests that trace the entire flow of the application from start to finish. These 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. Different testing platforms or frameworks can be used 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 then run again, multiple times if needed until they pass completely.


In this stage, the team plans and specifies the resources to be used in testing, the key testing tasks to cover, and all relevant testing schedules.


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


In this phase, the tests are executed following the plans and schedules, and testing results are properly documented.


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

End-to-End Testing Methods

End to end testing focuses on the entire functionality of the software and is therefore often targeted from the end-user's perspective. To design E2E testing, teams would often use one of two approaches, the vertical method, and the horizontal method.

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 order following the sequence of the hierarchy. 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 component parts of the software in detail.

Horizontal Method

This involves parallel testing of multiple software components at the same time. In the same testing run, tests are carried out horizontally over multiple 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 of time. These are then arranged according to their priority, which is assessed based on severity and consequence.
  • Progress Tracking – Tracking of test completion, expressed by a percentage, gathered over a defined time 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.
  • Case Preparation – This tracks the progress of actual completion of test case preparation against the planned rate of preparation.
  • Environment Availability – This tracks the actual amount of operational testing hours over a period of time against the planned number of hours for testing.

End-to-End Test Automation with Functionize

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

For an efficiently automated end to end testing workflow, you need a test automation platform that is resistant to fragile tests and can learn over time to make sure that tests are automatically healed and maintained. A platform that allows for easy and intuitive test creation and one that provides exhaustive, detailed data is an added bonus.

Functionize uses AI and machine learning to ease the test creation process while also making the tests more resistant to failure. With the right tool, companies can achieve efficient and effective end to end testing. Keeping in mind the absolutely crucial nature of this testing step, it's critical to pay adequate attention for the best results.


Considering the usual challenges in end-to-end testing, a testing platform like Functionize can bring to the table a number of important benefits that can help overcome these challenges and lead to a streamlined, intuitive, and optimized E2E testing workflow.

No Code Test Creation

The no code test creation process in Functionize X makes for an incredibly easy, codeless approach to test creation. This makes it easy for anyone in the testing team to create tests quickly. This way, it’s also easier to create reusable test components that can definitely have an impact on accelerating the end-to-end testing process.

AI-Driven Test Maintenance

Test maintenance being one of the most important challenges of end-to-end testing, the AI-driven test maintenance and test healing implemented by Functionize can help overcome this challenge. Tests created using Functionize automatically adapt to changes in the UI using AI and make test maintenance a lot easier.

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

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

To identify test scenarios, think about actual use case scenarios that need to be tested before release. This can be a group effort of brainstorming with the participation of testers, developers, and other stakeholders. It's a poignant idea to quickly come to a small running list of important scenarios and then later expand the list.

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

These can then be converted into actual test cases. You can then opt to run them manually where needed 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.

A testing platform like Functionize that leverages AI and machine learning to automatically keep up with test maintenance and help combat test fragility can be a big help in automated end to end testing.

Finally, you can add this automated end to end tests to your CI pipeline. This will provide important feedback to the development team and also help standardize the process of creating and running end to end tests.

End to End Test Example

A typical instance of end-to-end testing that involves, for example, software that works as a ticketing system for trains would involve entering the software URL and logging in with valid user credentials. From there, the user would enter the source and destination locations of the journey, the date of the journey, and the class of travel and should be able to see transport options.

The user should then be able to select their preferred option, select the number of tickets, and complete payment for the same using their preferred digital payment option. The flow ends with the user seeing a copy of the ticket on the screen with the option to get a printout, while another copy is automatically sent to the email address of the user.

E2E Testing Checklist

Many different components comprise end to end testing. A checklist for E2E testing can look at the following:

  • Testing the functionality of the software as a whole, keeping in mind the expected workflow during actual user interaction.
  • Testing the performance of the software system to make sure that it provides a uniform, seamless user experience while navigating.
  • Testing the data storage of the software to ensure that data can be properly stored, organized, retrieved, and updated as and when necessary.
  • Performing usability tests that ensure the degree of usability and ease of use of all the components of the software system as part of a typical user flow.
  • Performing security testing and vulnerability testing.


End to end testing, especially because of its approach and the mindset behind it, can be an incredibly important part of overall software testing. While other testing techniques are mostly technical and at component level, E2E testing deals with the actual user experience. For this reason, organizations should choose the right testing tools and devote adequate resources to end to end testing so as to deliver a consistent, high-quality user experience.