End-To-End Testing vs. Regression Testing: How To Decide Which Is Best For Your Needs

Testlio

July 26th, 2024

End-to-end (E2E) testing and regression testing are critical aspects of software testing that play very different roles. E2E Testing evaluates the entire application, simulating real user experiences. 

In contrast, regression testing checks if recent updates or changes have inadvertently disrupted existing functionality.

Choosing the right testing strategies is as important as testing frequently. But, you need to understand the differences between these testing methods before deciding which one to use for your testing needs. 

Let’s talk about end-to-end testing vs. regression testing to clarify how each approach works and when to use it.

What is End-to-End Testing? 

End-to-end testing is a type of software testing that validates an application’s complete workflow from start to finish. It ensures all integrated components and systems work together as intended. 

E2E testing evaluates the following aspects of an application or software:

• Product performance and functionality.
• Identification of dependencies and integration issues. 

Given the nature of end-to-end testing, it’s often challenging to perform this testing in a standard testing environment. Instead, a simulated or actual post-prelease environment is usually required. 

Importance of End-to-End Testing

E2E testing identifies performance issues that unit or integration tests might miss. By detecting bugs before the app is released to users, it ensures a smooth and responsive user experience (UX). 

Here are some reasons why end-to-end testing is essential:

• Identifies system bottlenecks: It helps identify performance issues that are not detected in unit or integration tests. Simulating real user interactions reveals slowdowns or inefficiencies to ensure a smooth and responsive user experience.

• Ensures integration compatibility: Applications often consist of multiple components and services. End-to-end testing verifies that these components work together smoothly to prevent unexpected issues triggered by changes in one part of the system affecting others.

• Improves user satisfaction: End-to-end testing validates the entire user journey to ensure the application meets user expectations for functionality and performance. It also helps identify user interface and experience issues that might be missed in other types of testing.

End-to-End Testing Process

Every engineering team and company will have a unique approach to end-to-end testing based on their specific needs, technical expertise, and organizational values. 

While exact processes may differ, the following steps provide a general framework for implementing E2E testing effectively:

• Gather Requirements: Clarify the project’s requirements. Define the scope, objectives, and resources required for testing. Collaborate with stakeholders to understand the application’s features, user scenarios, and business workflows.

• Develop a Testing Strategy: Create a detailed plan outlining the testing methodology. You may need to define test scenarios, prepare test data, and establish the overall approach for executing E2E tests.

• Set the Testing Environment: Build a testing environment that replicates the production setup. Ensure all necessary components, like databases and servers, are correctly configured. If using cloud-based setups, understand the specific configuration requirements.

• Design Test Cases: Based on the identified scenarios, develop comprehensive test cases that address various user interactions and system processes. For automated testing, consider principles like TRIMS (Targeted, Reliable, Informative, Maintainable, and Speedy) to guide your design.

• Conduct Tests: Execute the test cases to simulate user behavior and assess how the application performs under different conditions. Validate that data flows correctly and that the system operates as expected.

• Identify and Report Issues: Document any issues or variations encountered during testing. Provide detailed reports with steps to reproduce the problems and their impact on the system.

E2E Testing Example

To demonstrate end-to-end testing, let’s consider an e-commerce application example. 

Suppose a simulated scenario where a user starts on the home page of an e-commerce site to ensure all elements, such as images, product categories, and promotions, load properly. The user then selects a product and adds it to the cart to verify the different functionalities work as intended. 

For instance, the cart updates with the correct prices and quantity. The process continues through checkout, where the user enters shipping and payment details. This is to test the integration with payment gateways and form validation. 

The test ensures the order confirmation page and email are received, and finally, the user’s account shows the correct order history.

Understanding Regression Testing

Regression testing ensures that recent code changes have not broken existing functionality. This type of testing is typically done after any release or update. Testers re-run existing test cases, either partially or fully, based on the extent of the changes.

Regression testing encompasses various testing approaches, including functional, performance, and security testing. It also includes testing the integration between different software components. 

Furthermore, regression testing is a critical component of any continuous integration and continuous delivery (CI/CD) pipeline since it maintains system stability following each update. Identifying faults early decreases the need for extensive reworks and post-deployment defects, increasing user satisfaction. 

Regression Testing Example

Consider an online banking application where a new feature for transferring funds between accounts is added. Regression testing would involve re-running tests on existing features, such as checking account balances, viewing transaction histories, and paying bills. This helps ensure these functionalities still work correctly after the new transfer feature is integrated. 

This helps verify that the new feature hasn’t caused unexpected problems with the existing system.

End-to-End Testing vs. Regression Testing

End-to-end testing and regression testing are important in the software development lifecycle (SDLC) and are applied in distinct contexts. E2E testing covers the entire application workflow from start to finish, simulating real-user scenarios. 

On the other hand, regression testing includes re-running existing test cases to ensure recent changes haven’t affected existing functionality. 

E2E testing and regression testing also share some similarities, which include: 

• Both can be automated to improve efficiency and coverage.
• Both types of testing ensure the application’s reliability and performance.
• Both are essential for maintaining software quality during continuous integration and delivery.

Here’s a table demonstrating the differences between regression and end-to-end testing. 

End-to-End Testing vs. Regression Testing: Which One is Right for You?

When it comes to testing your software, you don’t have to choose between end-to-end and regression testing. Instead, you need to determine the right balance based on your needs.

E2E testing checks the entire application from start to finish, ensuring everything works together as it should. Regression testing, however, focuses on ensuring that recent changes haven’t disrupted any existing features.

Testlio can help maintain this balance through our solutions for both types of testing to simplify the process. Our various QA testing services ensure you launch high-quality products. 

Here’s what you get with Testlio’s fully managed regression testing:

• Customized regression testing with a mix of manual and automated methods.
• Bug fixes across various devices as part of the test cycles to ensure issues are resolved.
• A comprehensive end-to-end regression test during onboarding is needed to understand the app and its functionalities fully.
• Exploratory testing with each pass to uncover additional issues and provide maximum value.

Discover how Testlio can help you achieve rapid and reliable results! Explore our regression testing services, or visit our website to learn more about our QA solutions.