| name | regression-test |
| description | Run regression testing suite to verify existing functionality still works after changes |
Regression Testing Skill
Validates that existing functionality continues to work correctly after code changes, deployments, or dependency updates.
When to Use
- After code deployments
- After dependency updates
- Before releases
- After bug fixes
- After feature additions
- Periodic health checks
Capabilities
- Baseline comparison - Compare current behavior to known good state
- Critical path testing - Focus on essential functionality
- Change impact analysis - Identify areas affected by changes
- Automated execution - Run systematic regression tests
- Diff reporting - Highlight what changed from baseline
Workflow
Phase 1: Scope Definition
Determine regression scope based on changes:
- Full - Test all critical paths (major releases, risky changes)
- Targeted - Focus on areas affected by specific changes
- Smoke - Quick validation of core functionality (daily builds)
Phase 2: Baseline Identification
Establish expected behavior:
- Review previous test results as baseline
- Document expected responses and states
- Identify key acceptance criteria
- Note known issues to exclude
Phase 3: Test Suite Preparation
Organize tests by priority:
P0 - Critical Path (Always Run)
- Authentication flows
- Core feature functionality
- Data persistence
- Payment/checkout (if applicable)
P1 - Important Features
- Secondary features
- User management
- Settings and preferences
P2 - Edge Cases
- Error handling
- Boundary conditions
- Rare scenarios
Phase 4: Test Execution
Execute tests systematically:
- Run P0 tests first - stop if critical failures
- Continue with P1 tests
- Run P2 tests if time permits
- Capture evidence for all failures
- Note any new behaviors
Phase 5: Comparison Analysis
Compare results to baseline:
- New failures - Previously passing, now failing
- New passes - Previously failing, now passing (verify fix)
- Flaky tests - Inconsistent results
- Unchanged - Same as baseline
Phase 6: Reporting
Generate regression report:
- Tests executed vs baseline
- New issues found
- Fixed issues confirmed
- Overall regression status
- Recommendation (pass/fail)
Test Categories
Critical Path Tests
Essential functionality that must work:
- User authentication (login, logout, session)
- Core feature workflows
- Data creation and persistence
- Navigation and routing
- API integrations
Previously Fixed Bugs
Verify fixes haven't regressed:
- Run tests for recently fixed issues
- Confirm fix still in place
- Flag any regressions immediately
Integration Points
Test system interactions:
- API contract compliance
- Third-party integrations
- Database operations
- Cache behavior
Performance Baselines
Check performance hasn't degraded:
- Page load times
- API response times
- Memory usage patterns
Usage Examples
Full Regression (Before Release)
Use the regression-test skill to run full regression suite before the v2.0 release
Targeted Regression (After Change)
Use the regression-test skill to test user authentication after the password reset changes were deployed
Smoke Test (Quick Validation)
Use the regression-test skill for a quick smoke test before the demo
After Bug Fix
Use the regression-test skill to verify the login fix and ensure no regressions in authentication
Regression Report Format
# Regression Test Report
**Build/Version**: [Version]
**Date**: [Date]
**Scope**: Full / Targeted / Smoke
**Baseline**: [Previous test date/version]
## Summary
| Metric | Count |
|--------|-------|
| Tests Executed | X |
| Passed | X |
| Failed | X |
| New Failures | X |
| Fixed (Newly Passing) | X |
## Regression Status: PASS / FAIL
## New Failures (Regressions)
[List of tests that were passing but now fail]
## Fixed Issues (Newly Passing)
[List of tests that were failing but now pass]
## Unchanged Failures
[Known failures that remain - verify they're expected]
## Recommendation
[Ship / Block / Investigate]
Best Practices
- Maintain baselines - Keep expected results updated after intentional changes
- Prioritize tests - Run critical paths first
- Automate execution - Reduce manual effort
- Track trends - Monitor regression frequency over time
- Document intentional changes - So they're not flagged as regressions
- Run frequently - Catch regressions early
- Focus on changes - Prioritize areas affected by recent work
