A Comprehensive Guide to End to End (E2E) Testing

July 15, 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, like 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 definitely need to test if it works properly as a whole. This, in a nutshell, is the goal of end to end testing. Instead of testing for the functionality of individual components, end to end testing works on the system as a whole.

What is End to End (E2E) Testing?

End to end testing begins when the software reaches a stage of completion known as minimum viable product (MVP). Essentially, end to end testing is a software testing method where the application flow, from start to finish, is tested.

End to end testing goals can be broken down into two key components. First, this testing methodology ensures that all system dependencies have been met correctly. Second, it ensures that information flow between different system components is solid and accurate.

While end to end testing, by nature, differs from integration testing and unit testing, it is also not the same as UI testing. While there might be overlap, UI testing is considered to be more of a part of the unit testing methodology.

How does end to end testing work?

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 out breaks in this flow, which would provide indication of an error.

To create end to end tests, the process initially involves the 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 debugged. The tests are then run again, multiple times if needed until they pass completely.

Types of E2E tests

End to end testing focused on the entire functionality of the software and is therefore often targeted from the perspective of the end-user. To this end, end to end testing can be configured in two broad types - manual testing and automated testing.

In the manual testing route, one or more testers would act as the end-user, preferably across a variety of devices, screen sizes, and platforms. The testers would then replicate a common usage flow indicative of the intended use of the software to trace the activities from start to end. During this time, they would be alert for any break in the flow or impacted functionality.

Automated testing techniques try to achieve the same goals, but can use more intricate and sophisticated testing capabilities and scenarios. Compared with manual testing, a lot more can be achieved in a lot less time, leading to better test coverage.

E2E Testing Methods

To carry out end to end testing efficiently and seamlessly, it is important to establish a testing methodology that integrates best practices and situation-specific measures. Often, the main consideration while determining this methodology is the degree of opportunity to implement automation while preserving practicality and cost-effectiveness.

Since end to end testing deals with real user scenarios, it might be easier and cheaper to first set up and run manual tests. Simulating a production environment is easier with manual testing and entry costs are typically lower. In fact, for very simple software, manual testing might be sufficient to deal with most end to end testing demands.

On the other hand, manual testing involves the possibility of human error. After a while, manual testing is difficult to scale and can quickly become slow and cumbersome. In contrast, automating end to end testing might require some initial investment in terms of time and resources. Pertaining to this, over time, ROI can be significant.

E2E Testing vs. System Testing

While E2E testing and system testing can seem to be quite similar, there are quite a few qualitative differences that help distinguish between the two.

With system testing, the aim is to test the entire system and all its components to make sure that all functional requirements are fulfilled. This is usually done with the help of spec sheets and requirements lists and does not merit testing the system components in any particular order.

However, with end to end testing, it is the FLOW of the system that gets priority. This makes system testing more of a technical process while end to end testing is more of a simulation of the flow of actions that would take place when an actual end-user tries to use the software.

System testing usually involves functional testing and non-functional testing whereas end to end testing involves testing all backend systems and all interfaces.

For example, if using a software involves a number of actions or activities, these can be tested in any order as part of system testing. However, for end to end testing, they will be tested only in the order in which actual users would be expected to perform those actions.

System testing is typically introduced in the testing process right after integration testing is completed. However, end to end testing is usually only introduced in the testing process once system testing has been done.

End to End Testing Example

A typical instance of end to end testing that involves, as an example, a 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, date of 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.

How to Do E2E Testing Step by Step

A step by step breakdown of end to end testing involves identifying key test scenarios, mapping out the steps in each, 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 prior to 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, taking care to specify 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 these 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.

E2E Testing Checklist

There are many different components that make up end to end testing. A more or less generalized checklist for E2E testing can look this the following -

  • Testing the functionality of the software as a whole, as dictated by all the parts working together flawlessly according to the information flow expected with a standard users.
  • Testing the performance of the software system as it pertains to creating a uniform, seamless user experience as users navigate through the software.
  • Testing the data storage of the software to ensure that data can be properly stored, organized, retrieved, and updated as and when necessary.
  • Usability tests that can ascertain the degree of usability and ease of use of all the different components of the software system as part of a typical user flow.
  • Security testing and vulnerability testing.

End to End Test Automation for Modern Software Systems

As it is in most other areas of software testing, end to end testing can also benefit greatly from test automation. However, 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 efficiently automated end to end tests, 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.