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23 January 2024
09 Min. Read

Difference Between End To End Testing vs Regression Testing

Difference Between End To End Testing vs Regression Testing

Fast Facts

Get a quick overview of this blog

  1. Get to know about the differences between End To End Testing and Regression testing

  2. End To End Testing tests the system, while regression testing tests specific parts of the code.

  3. End-to-End Testing applies throughout SDLC with new tests; Regression Testing reuses tests post-changes.

  4. Learn about a smart automated approach to perform Regression testing.

The field of Software Testing is expanding rapidly, with new tools and technologies emerging daily. In this dynamic landscape, it is natural to encounter increased confusion and a limited understanding of the ongoing developments.

One particular area of complexity involves end-to-end testing and regression testing. While these two testing types differ significantly, they also exhibit numerous similarities. Notably, E2E testing may encompass regression testing, and vice versa, with E2E tests becoming integral to the regression cycle.

To alleviate any confusion and enhance comprehension of these concepts, we trust that this concise guide will prove beneficial.

End-to-End Testing vs. Regression Testing

Let’s address the elephant in the room first, and so let’s get to know about the differences between end-to-end testing vs regression testing. It’s completely okay to not get all the points clear in one-go, we’ll delve into details further for both these testing types.


End-to-End Testing

Regression Testing


End-to-end testing is a method where the complete software system is tested from start to finish.

Regression testing involves re-running functional and non-functional tests to ensure that previously developed and tested software still performs after a change.


Broad scope, covering the entire application from start to end.

Varies, but generally limited to specific functionalities that are impacted by changes.


To verify the overall system flow and ensure all integrated components work together as expected.

To identify any side effects caused by new changes or enhancements in the software.


Typically performed once after the completion of system testing.

Performed frequently, after every major code change or addition to the existing codebase.

Typical Use Cases

Testing workflows from end to end, such as database transactions, file processing, and user interfaces.

Testing after bug fixes, performance improvements, or other updates to ensure no new errors are introduced.

Tools Used

Selenium, TestComplete, Protractor, etc.

Selenium, HyperTest, Rational Functional Tester, etc.


Ensures the complete and correct flow of the application. Detects system-level issues.

Helps maintain software quality over time. Quickly identifies new bugs after changes.


Time-consuming and complex due to the testing of the entire system.

Requires maintaining a comprehensive test suite. Risk of not covering all impacted areas.

Now that we’ve looked into the differences and we broadly understand both the terms. Now let’s dive into both the concepts one-by-one and understand them with examples.

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What is End-to-End Testing?

End-to-end (E2E) testing is a comprehensive approach to software validation, where the objective is to assess the functionality and performance of an application in a way that mimics real-world scenarios. This method encompasses verifying all the integrated components of an application from start to finish, ensuring that the entire flow works as expected. It's not just about checking individual units or modules, but about testing the complete application in its entirety, including its interaction with external interfaces and databases.

E2E testing, simply put, means checking your whole app or system step by step, focusing on how it looks and works on the screen. Testers make sure that every part of the app does what it's supposed to and runs smoothly.

The goal of E2E testing is to simulate the user experience as closely as possible, identifying any issues that might occur in real-world use. This includes testing the application's interface, APIs, databases, network connectivity, and other external dependencies.

By doing this, testers can ensure that the system is not only functioning in isolation but also operates effectively when integrated into its intended environment.

Example of End-to-End (E2E) Testing

Scenario: Imagine a web-based e-commerce application where users can browse products, add them to their cart, and proceed to checkout.

1. E2E Testing Process:

  • The test begins with the user logging into the application.

  • The user then navigates through different product categories.

  • Next, the user selects a product and adds it to the shopping cart.

  • The user proceeds to the checkout process, entering payment and shipping information.

  • Finally, the user completes the purchase and receives a confirmation message.

2. Testing Goal:

  • The goal is to ensure that the entire process, from logging in to completing a purchase, works seamlessly and as intended.

3. Automated Test Code Example (using a tool like Selenium WebDriver in Python):

from selenium import webdriver

driver = webdriver.Chrome()

# Log in

# Browse products and add to cart

# Checkout

# Assert confirmation
assert "Thank You" in driver.page_source


Benefits of End-to-End Testing

  1. Detects System-Wide Issues: E2E testing uncovers problems that may not be visible in unit or integration testing. It helps in identifying issues related to data integrity, user interface, and overall system performance.

  2. Improves User Experience: By testing the application from a user's perspective, it ensures that the system is user-friendly, intuitive, and meets user requirements.

  3. Ensures Application Reliability: It verifies the system’s reliability and stability under different scenarios, including error or failure conditions.

  4. Validates Business Processes: End-to-end testing validates the application against defined business requirements, ensuring that all business processes are accurately executed within the system.

  5. Reduces Future Risks: By identifying and fixing issues early in the development cycle, it reduces the risk of future failures and associated costs for maintenance and bug fixes.

Challenges with End-to-End Testing

  1. Complexity and Resource Intensiveness: E2E testing is complex due to the involvement of multiple systems and components. It often requires significant resources in terms of time, personnel, and infrastructure.

  2. Environment Setup and Maintenance: Setting up a test environment that accurately mimics the production environment can be challenging and time-consuming.

  3. Flakiness: E2E tests can be flaky, meaning they may produce inconsistent results due to issues like network latency, external dependencies, and timing issues.

  4. Long Execution Time: Since E2E tests cover the entire application, they often take longer to execute compared to unit or integration tests.

  5. Challenges in Automation: Automating E2E tests is challenging due to the complexity and variability in user interactions and external interfaces.

Importance of End-to-End Testing

End-to-end testing is crucial for several reasons. Firstly, it provides assurance that the entire application, as a cohesive unit, functions as intended and meets business and user requirements. It's essential for verifying the overall quality of the software, especially for complex applications with multiple integrations and user paths.

Furthermore, E2E testing helps in identifying and rectifying issues that might not be evident in unit or integration tests, thereby preventing potential problems in the live environment. This is particularly important in scenarios where a failure could lead to significant financial or reputational damage.

Finally, it prepares the application for real-world scenarios, providing confidence to stakeholders and end users that the software will perform reliably and efficiently in the production environment. This aspect of testing ensures that when the software is released, it not only functions correctly but also delivers a positive user experience, aligning with the overall objectives of the software development project.

What is Regression Testing?

Regression testing is a critical aspect of software quality assurance that involves retesting a software application after changes or updates have been made to the code. The primary purpose of this testing is to ensure that new code changes have not adversely affected the existing functionalities of the application.

It's a way to confirm that the software that was working fine before is still working fine after the modifications.

This type of testing is not just about identifying new bugs or errors in the application's latest version; it's also about verifying that the application continues to operate as expected in areas that should not have been affected by recent code changes.

Regression testing can be performed at various levels of the software testing process, including unit, integration, and system testing.

Read more - What is Regression Testing? Definition, Tools, Examples

Example of Regression Testing

Scenario: A software application for managing personal finances, which includes features like adding income, tracking expenses, and generating reports.

  1. Regression Testing Process:

    • After a new feature is added, such as a tool for tax calculation, regression tests are run.

    • Tests include adding income, tracking expenses, and generating monthly reports to ensure these existing features are still functioning correctly.

  2. Testing Goal:

    • The goal is to confirm that the introduction of the new tax calculation feature hasn't disrupted any of the existing functionalities.

  3. Automated Test Code Example (using a tool like JUnit for a Java application):

import org.junit.Assert;
import org.junit.Test;

public class FinanceAppTest {
    public void testAddIncome() {
        FinanceApp app = new FinanceApp();
        Assert.assertEquals(1000, app.getBalance());

    public void testTrackExpense() {
        FinanceApp app = new FinanceApp();
        Assert.assertEquals(800, app.getBalance());

    public void testGenerateReport() {
        FinanceApp app = new FinanceApp();
        String report = app.generateReport();
        Assert.assertTrue(report.contains("Balance: 800"));

Benefits of Regression Testing

  1. Ensures Software Stability: Regression testing helps maintain stability in software applications by catching bugs that might inadvertently be introduced during updates or enhancements.

  2. Improves Quality: By repeatedly testing the application after each change, regression testing ensures high-quality software, free from regressions or backward incompatibilities.

  3. Facilitates Continuous Improvement: It allows for the continuous addition of new features and updates, ensuring that improvements don’t compromise existing functionalities.

  4. Enhances User Confidence: Regular regression testing assures end users and stakeholders of the application’s reliability and robustness, even after multiple iterations of updates or changes.

  5. Supports Agile Development: In agile methodologies, where changes are frequent and incremental, regression testing ensures each change integrates seamlessly with existing functionalities.

Challenges with Regression Testing

  1. Time-Consuming: As the software grows, the regression testing suite can become extensive, leading to longer test cycles.

  2. Resource Intensive: It requires significant resources in terms of manpower and computing power, especially for large and complex applications.

  3. Test Suite Maintenance: Maintaining an up-to-date and relevant test suite can be challenging as the application evolves.

  4. Automating Tests: While automation can speed up regression testing, creating and maintaining automated test scripts is often complex and time-consuming.

  5. Identifying Relevant Test Cases: Deciding which test cases to run for each change can be difficult, especially in large applications with numerous functionalities.

Importance of Regression Testing

Regression testing is crucial for maintaining software integrity over time. It ensures that existing functionalities continue to work as new features are added or existing ones are modified. This is especially important in today's fast-paced development environments, where continuous integration and continuous delivery (CI/CD) practices are common. Without regression testing, there's a higher risk of introducing new bugs into production, which can lead to user dissatisfaction and harm the overall reputation of the product.

Moreover, regression testing serves as a safety net that allows developers to make changes with confidence, knowing that any unintended consequences of those changes will likely be caught in the testing process. It plays a vital role in the software development life cycle by ensuring that software evolution does not lead to degradation of existing quality standards. As software becomes more complex and as customer expectations for quality rise, the role of regression testing becomes increasingly important in delivering a reliable and high-performing software product.

Better Way To Perform Regression Testing

Regression testing is best to perform when you’re updating your codebase, or adding/deleting any new feature. Since this agile development always requires you to be on your toes, regression testing becomes an integral part of their testing cycle.

When you need to perform something so often, say, in every sprint, its better to adopt automation. Along with saving your time, automation also proves effective when your app scales and it needs rapid testing and quick feedback.

HyperTest, our no-code API testing tool simplifies regression testing by automatically generating end-to-end integration tests from actual network traffic, thereby reflecting real user activity. This not only saves time but also enhances the accuracy of the tests.

FinTech apps being highly reliant on data and code updates, need stringent regression testing in place. With millions of transactions in the line, the margin for error is razor-thin. So, refer to this complete guide that tells on how FinTech apps can save themselves from app failures due to inadequate APIs.

Related to Integration Testing

Frequently Asked Questions

1. What is the difference between testing and regression testing?

Testing checks if a system works correctly, while regression testing ensures that new changes don't break existing functionality by retesting the entire system.

2. What is the biggest challenge in manual testing?

End-to-end testing evaluates the entire system's functionality, simulating real user scenarios to ensure seamless integration of all components.

3. Why is it called regression testing?

Regression testing aims to detect any "regression" or unintended changes in software functionality after new code is introduced, preventing the reoccurrence of previously fixed issues.

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