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End-to-End Testing vs. Regression Testing: A Simple Guide

August 30, 2022

min read

When it comes to software development, your mobile development team can perform many types of testing. End-to-end testing and regression testing are two important types of software testing that are often confused with one another. While both types of tests are important, they serve different purposes. In general, regression tests are designed to test a specific functionality, while end-to-end tests test the entire system from start to finish.
In this article, we'll take a closer look at each type of test, explore their differences and provide a simple guide on choosing the right testing approach for your project.

Introduction

Automated testing is a crucial part of agile software development. The two most common automated testing types are end-to-end and regression testing.

What is end-to-end testing?

End-to-end testing is focused on testing the entire system from start to finish. It includes everything from the UI to the backend database. End-to-end testing aims to ensure that the system under test behaves as expected from the user's perspective. End-to-end tests simulate real-world scenarios and how the system responds to various inputs.

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For example, imagine you are testing a mobile eCommerce website. End-to-end testing would involve verifying that all pages on the website are loaded correctly on mobile devices, that all buttons and links work as expected, and existing functionalities like the sign-in / sign-out process can be completed by users successfully.
Below is a simple diagram depicting end-to-end testing. Here, the user interacts with the UI, which triggers various events in the back-end. These events are processed by different components in the system before finally being stored in the database. The end-to-end test verifies that all these events have been processed as expected and that the data has been stored correctly in the database.

Figure 1: End-to-end testing

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Need for end-to-end testing

End-to-end tests are essential because they help ensure that the software product works as expected from the user's perspective. It is especially important for complex systems with many different components and integrations.

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Without end-to-end testing, it would be not easy to know if the system is indeed working as intended. For example, a system may have all its components working correctly, but if the user experience is poor, the system will not be successful.

Advantages of end-to-end testing

End-to-end testing has several advantages:

End-to-end testing helps in ensuring that the entire system is working as expected.
It can assess the quality of the user experience and find defects that other types of tests cannot.
End-to end tests can find bugs in any part of the system.

Disadvantages of end-to-end testing
End-to-end testing also has some disadvantages:

Setting up and maintaining end-to-end testing environments can be time-consuming and expensive.
End-to-end tests can be challenging to automate, especially for complex applications.
It is not easy to test all possible real-world scenarios.

How to Perform end-to-end testing

If you want to carry out end-to-end testing, there are some things you need to do:

Define the scope of your end-to-end tests: When defining the scope of your end-to-end tests, you need to consider what you want to test and how much coverage you need. You also need to decide whether to carry out manual or automated testing.
Set up your test environment: You need to set up a test environment that includes all the components of your system. It can be time-consuming and expensive, especially for complex systems.
Write your end-to-end tests: Once you have your test environment set up, you need to write your end-to-end tests. End-to-end tests should be written in a way that they can be easily automated by your team.
Run your end-to-end tests: Once you have written your end-to-end tests, you need to run them. You can run them manually or using an automation tool.
Analyze the results: After your end-to-end tests run, you need to analyze the results. It will help you find any defects that may be present in your system.

The figure below shows the end-to-end testing process:

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Figure 2: End-to-end testing process

What is regression testing?

Regression testing is a type of software testing that is used to verify that changes to the code have not introduced new bugs. Regression tests are typically run after changes have been made to the code to ensure that the changes have not caused any new issues.

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For example, imagine you are testing a mobile web application. After adding a new feature, you would want to run regression tests to ensure that the new feature has not caused any bugs in the existing functionality. For instance, you may want to verify that the login process still works correctly after a redesign of the homepage.

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Figure 3: Regression testing

Need for Regression Testing

Regression testing is important because it helps ensure that changes to the code have not introduced new bugs. This is especially important for critical systems where even a small change can have a major impact.

Advantages of Regression testing

Regression testing has several advantages:

Regressing testing helps ensure that changes to the code have not introduced new bugs.
Your team can use it to even test complex systems.
It can be run frequently and quickly by your team.

Disadvantages of Regression testing

Regression testing also has some disadvantages:

It can be time-consuming and expensive to set up and maintain.
It can miss bugs that only occur under certain conditions.

How to perform regression testing

Here are some tips on how to carry out regression testing:

Plan and design your tests: before you start writing code, it is essential to plan and create your tests. This will help you save time and money in the long run.
Choose the right tools: there are many different regression testing tools available. It is crucial to choose the right tool for your needs.
Automate your tests: automating your tests can save you a lot of time and money.
Keep your tests up-to-date: it is vital to keep your tests up-to-date. It will ensure that they are still relevant and accurate.
Execute your tests: once you have designed and implemented your tests, it is time to execute them. This will help you find any bugs in the system.
Analyze the results: after executing your tests, it is important to analyze the results. This will help you improve your tests and fix any issues.

The figure below shows the regression testing process:

Figure 4: Regression testing process

Differences between end-to-end testing and regression testing

There are a few key ways in which regression testing and end-to-end testing differ:

Purpose

As we mentioned, regression testing ensures that changes to the codebase don't break existing functionality. Regression testing aims to ensure that changes to the system have not introduced new bugs. It focuses on testing specific functionality.

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On the other hand, end-to-end testing is focused on testing the entire system from start to finish. End-to-end testing aims to ensure that the system under test behaves as expected from the user's perspective.

Scope

Regression testing is typically done on a smaller scale than end-to-end testing. It is because it's only focused on a specific part of the codebase (i.e., the changes made by your team).
End-to-end testing, on the other hand, covers the entire system.

Frequency

Regression testing is typically done more frequently than end-to-end testing. It is because it's less time-consuming and can be done on a smaller scale.
On the other hand, end-to-end testing is more time-consuming and is typically only done when there are major changes to the application.

Cost

Regression testing is typically less expensive than end-to-end testing. It is because it's less time-consuming and your team can do it on a smaller scale. On the other hand, end-to-end testing is more expensive due to the increased time and resources required. It is usually more expensive to set up and run than regression tests, but they offer greater coverage.

Skills

Both testers and developers can perform regression tests, but end-to-end tests are usually performed by testers.

Conclusion

End-to-end testing and regression testing are both important methods of software testing. They have different purpose, scope, frequency, cost, and benefits. Engineering leaders need to beware of the differences between these two types of tests to choose the right one for their needs.

If you're looking for a tool that can help you with both regression testing and end-to-end testing, Waldo is a good option. It can be used to automate the execution of test cases on iOS and Android devices.