end-to-end-testing-vs-regression-testing

End-to-End Testing vs Regression Testing - The Difference

Two key types of testing  –  End-to-End testing and Regression testing – are often discussed but can be easily confused. Though they both serve to validate software functionality, they approach testing from different angles and are essential at different stages of the development lifecycle.

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In this blog, we will explore the differences between End-to-End Testing and Regression Testing, explaining their roles, use cases, and benefits, as well as highlighting when and how they should be implemented in the development process.

e2e-vs-regression-testing

What is End-to-End Testing?

End-to-end testing (E2E Testing) is a testing approach designed to verify that the entire system works as expected from start to finish. The goal of End-to-End Testing is to simulate real-world user scenarios and ensure that all components of the system, whether it's the front-end, back-end, or databases, integrate properly and function together seamlessly.

e2e-testing-definition

In E2E Testing, the test environment mimics the production environment as closely as possible, ensuring that all components of the application work together as intended. This type of testing validates the workflow, functionality, and user experience of the application as a whole.

Purpose of End-to-End Testing

The primary purpose of E2E Testing is to ensure that the entire system functions as a cohesive unit. Unlike unit or integration testing, which focuses on isolated parts of the application, E2E Testing assesses the complete journey of a user from the initial interaction to the final action. It confirms that data flows correctly, user inputs are processed as expected, and system integrations work across all components.

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Techniques in End-to-End Testing

There are several strategies and tools available for performing End-to-End Testing. The most common approach involves writing user-centered test scenarios that replicate real-world actions. For instance, an E2E test for an e-commerce website might include the following steps:

  • Open the website.
  • Browse for products.
  • Add items to the cart.
  • Proceed to checkout.
  • Complete the payment.

How to Run End-to-End Tests

Define the scope of End-to-End Testing

Begin by identifying the critical user journeys that need to be validated. These should represent typical interactions within the system that users will perform regularly.

Choose the right tools

Depending on the application’s nature, choose the appropriate tools. Popular frameworks for E2E testing include Cypress, Selenium, and Playwright. These tools simulate user actions and can be configured to run tests in various browsers and environments.

Prepare the test environment

Set up an environment that mirrors the production system. This ensures that the tests are performed in a realistic setting and that any issues detected will reflect what users may experience in real-world conditions.

Write the test scenarios

Develop test scripts that cover essential workflows and use cases. These scripts should be easy to understand, maintain, and run automatically.

Execute the tests

Run the tests across multiple browsers and devices. Ensure that they are executed in parallel when possible to save time, especially for applications that need to be tested across different configurations.

Analyze and report the results

After test execution, analyze the results for any failures or issues. Addressing these issues early ensures that the software is user-ready and free from major glitches.

Example

If we use an online booking system for flights as an example, an End-to-End test could involve the following steps:

  • A user logs into their account.
  • The user selects a flight based on date, time, and destination.
  • The system fetches available flights, and the user proceeds to select a flight.
  • The user enters payment information and confirms the booking.
  • The system generates a confirmation page and sends an email to the user.

Each of these steps must work together, and any issues within the workflow can have a significant impact on the overall user experience.

What is Regression Testing?

Regression testing, on the other hand, is a type of testing focused on verifying that changes to the codebase – whether new features, bug fixes, or other updates – do not negatively impact the existing functionality of the software. The goal of Regression Testing is to catch any unintended side effects of modifications and ensure that previously working features continue to function as expected after updates are made.

In short, Regression Testing is concerned with making sure that nothing breaks as new code is integrated into the existing system.

Purpose of Regression Testing

The primary purpose of Regression Testing is to ensure that software changes don’t introduce new bugs or regressions in previously stable functionality. This type of testing is crucial when software undergoes frequent changes, such as during Agile development cycles, when new features are continuously added and bugs are fixed.

Techniques in Regression Testing

Regression testing often involves rerunning a selection of previously executed test cases to verify that everything still works as expected. However, instead of manually running all tests, teams often automate regression test suites to maximize efficiency.

types-of-regressions

Some of the commonly used approaches to Regression Testing include:

  • Retest All: All tests in the test suite are re-executed to ensure comprehensive validation. This is thorough but can be time-consuming.
  • Selective Regression Testing: Only the tests related to recent changes are executed. This approach is more time-efficient but may miss issues caused by unrelated changes.
  • Prioritized Regression Testing: Test cases are executed based on their priority and potential impact on the system, ensuring that the most critical features are tested first.

How to Run Regression Tests

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Identify the scope of changes

Before starting Regression Testing, assess the changes made to the software. This helps identify which parts of the application need to be tested more thoroughly.

Create a Regression Test Suite

Select and group test cases that should be part of the regression suite. These tests should cover both critical functionalities and areas affected by recent changes.

Automate the tests

Use test automation tools like Selenium, JUnit, or TestNG to automate the regression tests. Automation increases efficiency and ensures consistent test execution.

Execute the Regression Tests

Run the automated test cases across different environments to ensure that the changes have not caused any new issues. Ensure that the tests cover various browsers, devices, and operating systems if applicable.

Review the results

After execution, review the test results for any failures. Investigate failed tests to identify whether the issue was caused by the recent changes or by an existing defect.

Example

Imagine you are working on an e-commerce website, and a new feature for gift card payments has been added. Regression Testing might focus on the following:

  • Verifying that the gift card payment method works.
  • Ensuring that adding a gift card as a payment option doesn’t affect other payment methods.
  • Checking that order confirmation emails are correctly generated for all payment methods.

End-to-End Testing vs Regression Testing: Key Differences

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Metrics for evaluating testing effectiveness

End-to-End testing metrics

  • Test Coverage: The percentage of critical user journeys covered by tests.
  • Test Execution Time: The time taken to run the full set of E2E tests.
  • Defect Detection Rate: The number of issues detected during testing, helping to assess test effectiveness.

Regression Testing metrics

  • Defect Detection Percentage (DDP): Tracks the number of defects found in regression tests versus all defects found, showing how effective the tests are at identifying new issues.
  • Test Case Pass Rate: The percentage of regression test cases that pass without issues.
  • Test Execution Frequency: How often regression tests are run, which is crucial for ongoing software stability.

Use cases: When to use End-to-End Testing vs Regression Testing

End-to-End Testing use cases

  • Pre-release validation: Ensuring the entire application functions as expected before it goes live.
  • Integration of major features: When significant new functionality or features are added, it’s critical to ensure all components work together seamlessly.
  • Critical user flows: Testing key user workflows, such as registration, checkout, or login, to ensure smooth operation.

Regression Testing Use Cases

  • Frequent software changes: After every code change, bug fix, or new feature introduction, Regression Testing ensures that the new code doesn't introduce problems in existing features.
  • Version upgrades: When upgrading or migrating systems, Regression Testing is essential to ensure the system still behaves as expected after the update.

Conclusion

End-to-End Testing and Regression Testing are both essential testing methods, but they address different aspects of the software. End-to-end testing ensures that the system works as a whole, mimicking real-world user interactions, while Regression Testing focuses on ensuring that new changes do not negatively impact the existing functionality.

By understanding the distinct roles of these two testing approaches and implementing them effectively at the right stages of the software development lifecycle, teams can ensure that their software delivers a flawless user experience and maintains its integrity as new features are added or updated.

What Global App Testing (GAT) offers: Elevating End-to-End and Regression Testing

Global App Testing (GAT) provides comprehensive testing solutions that cater to the diverse needs of modern software development. With its unique crowdsourced approach, GAT ensures real-world testing across a wide array of environments, enhancing the quality of software through unparalleled coverage and detailed insights.

Core services

  • End-to-End Testing: Validates the complete user journey, ensuring that all components of the system integrate seamlessly and function as intended.
  • Regression Testing: Ensures that new updates or changes do not interfere with existing functionality, maintaining system stability and reliability.
  • Exploratory Testing: Detects hidden defects beyond scripted test cases, offering a deeper understanding of the software’s behavior.
  • Test Case Execution: Executes predefined test cases consistently, ensuring accurate and reliable results throughout the testing process.
  • Localization Testing: Assesses the cultural and linguistic suitability of applications for global markets, enhancing user experience across regions.
  • Usability and UX Testing: Focuses on optimizing the user experience through detailed evaluations, ensuring the software is intuitive and easy to use.

A unique crowdsourced approach

GAT’s global community of over 90,000 testers is at the heart of its testing strategy. Operating from real-world environments, these testers provide valuable insights by simulating the conditions actual users will experience. This crowdsourced model uncovers issues that traditional testing methods may miss, ensuring that applications meet user expectations across different platforms, devices, and regions.

Focus on End-to-End and Regression Testing

  • End-to-End Testing: GAT’s approach to End-to-End Testing ensures comprehensive validation of the entire system. From the user interface to the back-end components, GAT’s global testers perform realistic tests to verify that all parts of the system work harmoniously, delivering a smooth, cohesive experience.
  • Regression Testing: With its large, diverse pool of testers, GAT accelerates the regression testing process, ensuring that updates or code changes do not disrupt existing functionality. By testing in real-world scenarios, GAT helps detect defects early and ensures the stability of the software post-deployment.

Key benefits of GAT’s testing approach

Faster Testing Cycles: GAT’s expansive global tester network enables quicker turnaround times for testing, speeding up the development process without sacrificing quality.

  • Unmatched Coverage: With testers spread across different devices, platforms, and user environments, GAT ensures unparalleled coverage for your software.
  • Real-World Insights: GAT’s crowdsourced approach reveals issues that often go unnoticed in traditional testing environments, offering valuable insights into how the software performs in real-world conditions.
  • Expert Collaboration: GAT bridges the gap between testing teams and developers, facilitating smoother communication and faster issue resolution, ensuring a more efficient development cycle.

Interested in learning more about how GAT can enhance your testing strategy?
Schedule a call with our specialist today!

We can help you drive software testing as a key initiative aligned to your business goals

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