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8.9. Regression Testing

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Regression testing is performed to ensure that newly implemented changes do not negatively impact existing system functionality.

The goal of this phase is to validate the stability of the overall application before release.

8.9.1 Objectives

  • Verify existing functionality remains stable
  • Ensure no regressions introduced by recent changes
  • Validate critical system workflows
  • Confirm overall application stability
  • Provide quality signal for release decision

8.9.2 Testing Environment

Regression testing is typically performed in the Pre-Production environment where the system configuration is closest to the production environment.

8.9.3 QA Activities

flowchart TB
    A["Define Regression Scope<br>(features, dependencies, time)"] --> B["Prioritize Tests<br>(high priority first)"]
    B --> C["Automated Regression Testing"] & D["Manual Regression Validation"]
    C --> E["Regression Test Suite Execution"]
    D --> E
    E --> F["Stability Validation"]
    F --> G["Defect Identification"]
    G --> H["Regression Result<br>(Ready / Issues Found)"]

    style A fill:#FFCDD2,color:#000000
    style B fill:#FF6D00,color:#000000
    style C stroke:#000000,fill:#FFD600,color:#000000
    style D fill:#FFD600,color:#000000
    style E fill:#FFE0B2,color:#000000
    style F fill:#FFF9C4,color:#000000
    style G fill:#C8E6C9,color:#000000
    style H fill:#00C853,color:#000000
During this phase QA performs the following activities:

Automated Regression Testing - executing automated regression tests when available to validate core system functionality - running automated test suites in CI/CD pipeline - validating critical paths through automation - monitoring automated test results and failures

Regression Test Suite Execution - executing regression test suites covering critical system functionality - validating core features and key user workflows - testing critical business processes - verifying essential integrations and system operations

Manual Regression Validation - performing manual regression validation of key application features and user interfaces where automation coverage is limited or not available - testing UI components and visual elements - validating user experience and usability - testing scenarios not covered by automation

Stability Validation - validating previously stable features after recent changes - confirming no unexpected behavior in existing functionality - testing system performance and responsiveness - verifying data integrity and consistency

Defect Identification - identifying defects introduced by recent development changes - documenting regression issues with clear reproduction steps - classifying defects by severity and impact - prioritizing issues for resolution

Regression testing scope is defined based on the newly implemented functionality, its dependencies, and available testing time.

Test execution is prioritized to ensure that the most critical and high-priority scenarios are validated first.

Automated regression tests are executed in full (where available) to provide comprehensive coverage of critical system functionality.

8.9.4 Entry Criteria

Before regression testing begins:

  • System testing completed
  • Build deployed to Pre-Production environment
  • Regression test suite prepared and accessible
  • Test data and accounts available
  • Environment stable

8.9.5 Quality Gates

  • All automated and manual regression tests are executed and results are documented
  • No critical/blocker defects remain after regression
  • Test cases and documentation are updated
  • Quality metrics are collected and analyzed
  • Regression status is communicated to the team and stakeholders

8.9.6 Automation Support

Regression testing benefits from automation:

  • Automated Suites – execute repetitive test scenarios consistently
  • CI/CD Integration – automated tests run on each build
  • Fast Feedback – quick identification of regressions
  • Coverage – comprehensive validation of critical paths

Manual testing complements automation:

  • UI Validation – visual and layout verification
  • Exploratory Testing – investigating unexpected behaviors
  • New Scenarios – testing recently changed areas
  • Usability – evaluating user experience

8.9.7 Outcome

The outcome of this phase typically includes:

  • validated stability of existing application functionality
  • confirmation that recent changes did not introduce regressions
  • identified defects affecting previously stable system areas
  • confirmation that automated regression tests (if available) pass successfully
  • documented regression test results
  • quality assessment for release readiness

8.9.8 Success Criteria

  • Automated tests passed (if available)
  • Regression test suite executed completely
  • Manual regression validation completed
  • No critical regressions identified
  • All identified issues documented
  • Test results communicated to stakeholders
  • Release readiness decision supported by data

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