Retesting vs. Regression Testing

Software testing is one of the most critical phases in the Software Development Life Cycle (SDLC).

Among the many testing strategies, two often-overlapping but fundamentally different types play a key role in maintaining product stability: Retesting and Regression Testing. These terms are frequently confused, yet they serve very distinct purposes.

This training guide will help you understand:

• What Retesting and Regression Testing are

• Why they matter

• Who is responsible for them

• How and when to perform them

• Real-world examples

• Best practices for integrating them into your development workflow

1. Why Testing Matters

Before we jump into the differences, let’s establish why these testing strategies exist.

Every change in software—whether it’s a bug fix, performance improvement, or new feature—can unintentionally impact other parts of the system. Without robust testing, these changes can introduce new issues or even break existing functionality. As a result, testing not only helps verify correctness but also protects the user experience.

Two key testing methods help achieve this: Retesting and Regression Testing.

2. What is Retesting?

Definition

Retesting is the process of checking whether a specific defect that was previously reported and fixed is now resolved. It’s focused, intentional, and repetitive.

Purpose

The goal is to verify that the original issue no longer exists and that the fix works as expected under the same conditions where it previously failed.

Key Characteristics

• Scope: Narrow (single bug or issue)

• Timing: After a defect is marked “fixed” by the development team

• Test Cases: Often reuses failed test cases from previous testing cycles

• Method: Mostly manual, as automation may not be justified for isolated defects

Who Performs Retesting?

• QA Analysts

• Testers

• Sometimes developers (particularly in smaller teams or during unit testing)

Example Scenario

Let’s say your mobile banking app crashed whenever users tapped the “Transfer Funds” button. After developers fix the issue, the QA team runs the same set of test steps to confirm that the crash no longer occurs. If the app behaves as expected, the retest passes.

This is retesting—simple, targeted, and necessary.

3. What is Regression Testing?

Definition

Regression Testing is a broader approach that checks whether recent changes (such as code updates, enhancements, or bug fixes) have negatively impacted existing functionality.

Purpose

The goal is to ensure that the rest of the system still works correctly after new changes have been introduced.

Key Characteristics

• Scope: Broad (entire application or major modules)

• Timing: After any code modification, not just bug fixes

• Test Cases: Based on a comprehensive suite of test cases covering core functionalities

• Method: Often automated, especially in Agile, DevOps, and CI/CD environments

Who Performs Regression Testing?

• QA Analysts

• Testers

• Developers (particularly when leveraging automated regression suites)

• Business Acceptance Testing (BAT) teams

Example Scenario

Continuing with the mobile banking app example—imagine that the team has now added a new biometric login feature. After deploying this feature, regression testing ensures that the previously working functionalities—like fund transfers, balance checks, and settings updates—still function correctly. If adding biometrics breaks the “Transfer Funds” feature, the regression test suite should catch it.

4. Retesting vs Regression Testing: Key Differences

To clarify the distinction, let’s look at a side-by-side comparison:

5. How These Testing Methods Fit into the SDLC

Retesting and regression testing both have specific places in the Software Development Life Cycle. Understanding when and where they apply helps teams manage workload, reduce technical debt, and avoid critical production issues.

Unit Testing (Early Stage)

• Performed by developers to test individual components.

• Regression testing may be partially involved here if reused modules are updated.

System and Integration Testing (Middle Stage)

• QA and test teams test integrated modules as a system.

• Retesting often takes place here after bug fixes are submitted.

• Regression testing ensures new modules didn’t break the system.

User Acceptance Testing (UAT)

• Business stakeholders ensure the software meets their needs.

• Regression testing ensures business workflows haven’t been disrupted.

• Retesting may also occur if UAT users find bugs that were thought to be fixed.

Production Release (Final Stage)

• Before go-live, a regression test is typically run again to confirm end-to-end stability.

• Smoke testing may be added to verify core features are up post-deployment.

6.  E-Commerce Checkout Flow

Initial Issue:

Users couldn’t apply a discount code at checkout. QA reports the bug. Developers fix the logic handling promo codes.

Retesting:

QA re-runs the specific scenario to confirm that the discount code is now applied correctly.

Parallel Change:

In the same release, the team adds a new payment method (e.g., Apple Pay).

Regression Testing:

QA runs a full checkout regression suite to ensure:

• Existing payment methods work (Visa, PayPal, etc.)

• Discounts still apply properly

• Items are correctly added/removed from the cart

• Order summary, taxes, and shipping calculations remain accurate

Outcome:

Because both retesting and regression testing were done properly, the release is successful and error-free in production.

7. Who’s Involved and Why It Matters

Testing is a team sport. Multiple roles participate at different levels to ensure quality. Here’s how each one contributes:

QA Analysts & Testers

• Own the execution of both retesting and regression test suites

• Design, update, and maintain test cases

• Often coordinate closely with developers on test coverage

Developers

• Fix defects and sometimes run unit tests or automated regression tests

• Help maintain automated test scripts

• Assist with testing in DevOps or CI/CD pipelines

Product Owners (POs)

• Prioritize bug fixes and enhancements

• Ensure critical business features are included in regression testing

• Validate that acceptance criteria are met

Business Acceptance Testing (BAT) Teams

• Validate that the software aligns with business expectations

• Participate in regression testing from a business flow perspective

User Acceptance Testing (UAT) Groups

• Represent end-users and ensure usability

• May participate in regression testing from a customer experience point of view

8. Best Practices for Effective Retesting and Regression Testing

✅ Maintain Separate Test Suites

Keep your regression test cases organized in a suite that evolves with your product. Retesting cases should be short-lived and tightly scoped to the specific defect.

✅ Automate When It Makes Sense

Regression testing is repetitive and ideal for automation. Use tools like Selenium, Cypress, or built-in CI/CD integrations to run automated tests on every commit.

✅ Prioritize High-Risk Areas

Focus your regression efforts on areas that are most likely to break—such as login systems, payment processing, or user settings.

✅ Track Test Coverage

Use traceability matrices or test management tools like Zephyr, Xray, or TestRail to track which requirements and scenarios are being tested.

✅ Integrate Testing into Your Agile Process

Include regression test planning as part of sprint planning. Schedule retesting tasks immediately after developers resolve defects.

Retesting and Regression Testing may sound similar, but they serve very different roles in maintaining software quality. Think of retesting as confirming a bandage was applied correctly—and regression testing as checking that the rest of the body is still healthy.

Together, these practices ensure that software changes don’t introduce chaos into your product. When integrated properly into your development process, they reduce risk, improve reliability, and build user trust.

By understanding when, why, and how to use both testing methods, IT teams can work more efficiently and release with confidence.