Confirmation Testing and Regression Testing: Complete ISTQB CTFL Guide

Confirmation Testing and Regression Testing in SDLC

Introduction

Confirmation Testing and Regression Testing are two critical quality assurance techniques that ensure software maintains its quality throughout the Software Development Lifecycle (SDLC). These testing approaches work together to verify that defects are fixed and that existing functionality remains unaffected by changes.

Why Confirmation Testing and Regression Testing Are Important

Confirmation Testing Importance:

• Defect Verification: Ensures that bugs identified during testing have been properly fixed by developers
• Quality Assurance: Provides confidence that reported issues have been resolved
• Cost Effectiveness: Catches regressions early before moving to further testing phases
• Communication: Facilitates clear communication between developers and testers about defect resolution
• Compliance: Helps meet quality standards and regulatory requirements

Regression Testing Importance:

• Risk Mitigation: Identifies unintended side effects caused by code changes
• Stability Assurance: Ensures existing functionality continues to work after modifications
• Release Confidence: Provides assurance that new features don't break established functionality
• Maintenance: Essential during patches, updates, and bug fixes
• Long-term Quality: Maintains software quality as it evolves and matures

What Is Confirmation Testing?

Definition:

Confirmation Testing, also known as Re-testing, is the process of verifying that defects previously identified and reported have been successfully fixed by the development team. It involves re-executing test cases that originally failed to confirm that the issues have been resolved.

Key Characteristics:

• Focused Scope: Tests only the specific functionality that was reported as defective
• Targeted Approach: Re-executes the exact test cases that previously failed
• Short Timeframe: Typically performed immediately after a defect fix
• High Priority: Usually conducted before any other testing activities on the modified code
• Binary Outcome: Confirms whether the defect is fixed (pass) or still exists (fail)

What Is Regression Testing?

Definition:

Regression Testing is the process of executing previously executed test cases on a modified or new version of the software to ensure that existing functionality has not been adversely affected by recent changes. It verifies that new code changes don't introduce unintended defects in unchanged areas of the system.

Key Characteristics:

• Broad Scope: Tests the entire application or significant portions of it
• Preventive Nature: Identifies side effects and unexpected interactions
• Ongoing Process: Performed after any code changes, including bug fixes and enhancements
• Non-targeted: Tests areas that may have been indirectly affected by changes
• Risk-based Selection: Often focuses on high-impact areas and frequently used features

Confirmation Testing vs. Regression Testing

How Confirmation Testing Works

Step-by-Step Process:

1. Defect Reception and Analysis

• Receive a bug report from testers or users
• Analyze the defect description, reproduction steps, and expected versus actual behavior
• Understand the severity and impact of the issue

2. Test Case Preparation

• Identify the original test case(s) that revealed the defect
• Document the exact steps to reproduce the issue
• Gather any necessary test data and environmental setup

3. Defect Fix by Development

• Development team implements the fix
• Code changes are completed and committed
• The fixed build is provided to the testing team

4. Execution of Confirmation Tests

• Execute the original failing test case(s) against the fixed build
• Verify that the issue is resolved under the same conditions
• Verify that the fix works as intended

5. Result Evaluation

• If Passed: Confirm that the defect is fixed; update defect status to 'closed' or 'resolved'
• If Failed: The defect still exists; return it to development with additional information

Example Scenario:

A tester reports that the login button is not working when the username field contains special characters. The developer fixes the input validation logic. The tester then executes the same test case with special characters to confirm that the login now works correctly. This is confirmation testing.

How Regression Testing Works

Step-by-Step Process:

1. Test Suite Preparation

• Maintain a comprehensive test suite of previously executed tests
• Select test cases based on risk assessment and impact analysis
• Prioritize tests for critical and frequently used features

2. Code Change Implementation

• Development team implements new features or fixes bugs
• Code changes are integrated into the build
• A new build is created for testing

3. Test Case Selection

• Apply risk-based testing to select regression tests
• Include tests for areas directly affected by changes
• Include tests for areas indirectly affected (dependencies)
• Include smoke tests for core functionality

4. Test Execution

• Execute selected regression test cases
• Verify that all previously passing tests still pass
• Document results and any new failures

5. Defect Handling

• Any new failures indicate regression defects
• Report these defects with detailed information
• Prioritize fixes based on severity

6. Confirmation and Closure

• Once regression defects are fixed, run confirmation tests
• Re-run regression tests to ensure complete stability

Example Scenario:

A development team modifies the payment processing module to add support for a new payment method. Before releasing this change, the QA team runs regression tests on the entire payment system, including existing payment methods, transaction history, receipt generation, and refund processing. This ensures that adding the new payment method hasn't broken any existing functionality.

Regression Testing Strategies

1. Selective Regression Testing

• Execute only test cases related to the modified components
• Most practical for large test suites
• Reduces testing time and costs
• May miss unexpected side effects in distant components

2. Complete/Full Regression Testing

• Execute the entire test suite
• Most thorough approach
• Time-consuming and resource-intensive
• Often impractical in Agile environments with frequent changes

3. Risk-Based Regression Testing

• Prioritize tests based on risk and impact analysis
• Focus on high-risk areas and frequently used features
• Balance between thoroughness and efficiency
• Requires good understanding of system architecture and dependencies

4. Smoke Testing (as part of Regression)

• Quick, high-level tests of critical functionality
• Early detection of major issues
• Performed before comprehensive regression testing
• Often automated for faster feedback

Automation in Confirmation and Regression Testing

Importance of Automation:

• Efficiency: Automated tests execute much faster than manual testing
• Consistency: Automation eliminates human error and ensures consistent test execution
• Cost-Effectiveness: Over time, automation reduces testing costs
• Quick Feedback: Enables continuous integration and continuous deployment (CI/CD)
• Repeatability: Same tests can be run repeatedly with minimal effort

Best Practices for Automated Regression Testing:

• Build and maintain a robust automated test suite
• Prioritize automation of critical and frequently run tests
• Use test data management to ensure consistent test environments
• Implement continuous integration to run tests automatically
• Regularly review and update automated tests
• Combine automated and manual testing for optimal coverage

Exam Tips: Answering Questions on Confirmation Testing and Regression Testing

Understanding Exam Question Patterns:

Tip 1: Distinguish Between the Two

Many exam questions test whether you can differentiate between confirmation and regression testing:

• Look for keywords: 'verify fix,' 'defect,' 'specific issue' → Confirmation Testing
• Look for keywords: 'side effects,' 'existing functionality,' 'unintended,' 'changed code' → Regression Testing
• Remember: Confirmation tests a specific defect, while regression tests everything else

Tip 2: Know the Sequence

Questions often ask about the proper order of testing activities:

• Confirmation testing comes after a defect is fixed
• Regression testing comes after any code change (which may include the confirmed fix)
• Typical sequence: Defect found → Fix applied → Confirmation test → Regression test

Tip 3: Recognize Typical Exam Questions

Question Type 1: Scenario-Based

Example: 'A bug was found where users couldn't upload files larger than 5MB. The developer fixed the issue. What should the tester do next?'

• Answer: Execute confirmation tests using files larger than 5MB to verify the fix
• Don't be tempted to immediately run all tests (that's regression)

Question Type 2: Defect Status

Example: 'When should a defect be marked as 'Resolved'?'

• Answer: After confirmation testing passes, confirming the fix is successful

Question Type 3: Test Case Selection

Example: 'Which test cases should be included in regression testing after modifying the user authentication module?'

• Answer: Previously passed tests related to authentication and potentially dependent modules
• Not just the specific failing test that was fixed

Tip 4: Focus on Risk and Impact

• Regression testing is risk-based
• High-risk modules get more thorough testing
• Unrelated modules may not need regression testing
• Questions often test understanding of impact analysis

Tip 5: Understand Automation Context

• Regression testing is frequently automated due to repetition
• Confirmation testing can be manual or automated
• Questions may ask about automation strategy for regression tests
• Know the benefits: speed, consistency, efficiency

Tip 6: Know the Relationship to SDLC Phases

• Both testing types occur throughout the SDLC
• More frequent in later phases (system testing, UAT)
• Common in maintenance phase
• Essential in Agile environments with frequent releases

Common Incorrect Answer Patterns to Avoid:

Mistake 1: Confusing the Scope

• Wrong: 'Regression testing verifies that the specific defect is fixed'
• Correct: 'Confirmation testing verifies that the specific defect is fixed'

Mistake 2: Wrong Timing

• Wrong: 'Run regression tests, then if they pass, run confirmation tests'
• Correct: 'Run confirmation tests after the fix, then run regression tests on the broader system'

Mistake 3: Test Case Selection Errors

• Wrong: 'Confirmation testing uses new test cases to discover related issues'
• Correct: 'Confirmation testing uses the same test case that previously failed'

Mistake 4: Scope of Regression

• Wrong: 'Regression testing only tests the modified component'
• Correct: 'Regression testing tests the modified component and potentially affected areas'

Quick Reference for Exam Day:

Sample Exam Questions and Answers:

Question 1:

A critical bug in the payment processing system is fixed. What is the primary objective of confirmation testing in this scenario?

A) To find additional bugs in the payment system
B) To verify that the reported payment bug is actually fixed
C) To ensure no other modules were affected
D) To validate the entire payment workflow

Correct Answer: B

Explanation: Confirmation testing specifically verifies that the reported defect has been fixed. Options A and D are too broad (that's regression testing), and Option C relates to regression testing rather than confirmation.

Question 2:

After implementing a new feature in the user registration module, which testing approach should be applied to ensure that existing login functionality has not been affected?

A) Confirmation testing of the registration feature
B) Regression testing of the login functionality
C) Confirmation testing of both features
D) Only smoke testing

Correct Answer: B

Explanation: Regression testing ensures existing functionality (login) hasn't been broken by new changes. Option A would test the new feature itself, which is not the concern here. Option C is partially correct but the primary focus should be regression testing for existing functionality.

Question 3:

In a test execution workflow, confirmation testing should occur:

A) Before developers fix the defect
B) After the defect is fixed and before regression testing
C) As part of regression testing
D) After all regression testing is complete

Correct Answer: B

Explanation: The proper sequence is: defect identified → fix applied → confirmation testing (verify fix) → regression testing (verify no side effects). Option B correctly places confirmation testing in the workflow.

Conclusion

Confirmation Testing and Regression Testing are essential testing techniques throughout the SDLC. Confirmation Testing provides focused verification that specific defects have been resolved, while Regression Testing ensures that changes don't introduce unintended side effects. Understanding the distinction between these two approaches, their purposes, execution strategies, and proper timing is critical for success in ISTQB CTFL examinations.

Key takeaway: Confirmation Testing = Did we fix this specific bug? Regression Testing = Did we break anything else?