Regression Test

Regression Test Skill

You are facilitating the Regression Testing process. Your role is to run tests after changes and verify no existing functionality is broken.

Purpose

Regression testing ensures:

• Existing functionality stays intact after changes
• Tests cover critical paths
• Test failures are properly documented
• Changes are validated before merge

Testing Flow

IDENTIFY SCOPE -> PRE-CHECK -> RUN TESTS -> ANALYZE RESULTS -> REPORT -> FIX IF NEEDED

Workflow

Phase 1: Identify Scope

1. Parse testing request
2. Identify what changed (from git diff)
3. Determine affected test categories:
   • Unit tests
   • Integration tests
   • E2E tests
4. Prioritize tests by affected areas

Phase 2: Pre-Check

Before running tests:

• Dependencies installed
• Environment configured
• Database migrations applied
• Services running (if integration tests)

Phase 3: Run Tests

Run test suites in order:

1. Unit Tests (fast, isolated)

   • Frontend component tests
   • Backend service tests
   • Database model tests

2. Integration Tests (slower, connected)

   • API endpoint tests
   • Frontend + API integration
   • Database integration

3. E2E Tests (slowest, full stack)

   • Critical user flows
   • Cross-domain functionality

Phase 4: Analyze Results

For each test:

• Pass: Document
• Fail: Investigate root cause
• Skip: Document reason

Phase 5: Report

Generate test report with:

• Summary (pass/fail counts)
• Failed test details
• Coverage metrics
• Recommendations

Phase 6: Fix If Needed

If tests fail:

1. Analyze failure cause
2. Determine if change broke test or test is wrong
3. Fix code or update test
4. Re-run to verify

Test Report Template

# Regression Test Report

**Date**: [Date]
**Trigger**: [What triggered this test run]
**Scope**: [What tests were run]

---

## Summary

| Category | Total | Passed | Failed | Skipped |
|----------|-------|--------|--------|---------|
| Unit Tests | [n] | [n] | [n] | [n] |
| Integration Tests | [n] | [n] | [n] | [n] |
| E2E Tests | [n] | [n] | [n] | [n] |
| **Total** | [n] | [n] | [n] | [n] |

**Status**: PASS / FAIL

**Coverage**: [percentage]%

---

## Failed Tests

### [Test Name]
- **File**: [test file path]
- **Error**: [error message]
- **Cause**: [root cause analysis]
- **Action**: [Fix code / Update test / Known issue]

### [Test Name 2]
- **File**: [test file path]
- **Error**: [error message]
- **Cause**: [root cause analysis]
- **Action**: [Fix code / Update test / Known issue]

---

## Skipped Tests

| Test | Reason |
|------|--------|
| [Test name] | [Reason for skipping] |

---

## Coverage Metrics

| Domain | Coverage | Target | Status |
|--------|----------|--------|--------|
| Frontend | [%] | 80% | PASS/FAIL |
| Backend | [%] | 80% | PASS/FAIL |
| Database | [%] | 70% | PASS/FAIL |

---

## Recommendations

1. [Recommendation 1]
2. [Recommendation 2]

---

## Action Items

| Priority | Action | Assignee |
|----------|--------|----------|
| P1 | [Fix failed test] | [Agent] |
| P2 | [Add missing test] | [Agent] |

---

## Next Steps

- [ ] Fix failed tests
- [ ] Re-run regression
- [ ] Merge if all tests pass

Test Categories by Domain

Frontend Tests

• Component rendering tests
• Hook behavior tests
• Integration tests (API calls)
• Accessibility tests
• Responsive design tests

Backend Tests

• API endpoint tests
• Service layer tests
• Model/validation tests
• Authentication tests
• Error handling tests

Database Tests

• Model integrity tests
• Migration tests
• Query performance tests
• Constraint tests

Test Commands

Frontend (React/Vue)

# Unit tests
npm run test:unit

# Integration tests
npm run test:integration

# E2E tests
npm run test:e2e

# Coverage
npm run test:coverage

Backend (FastAPI/Flask)

# Unit tests
pytest tests/unit

# Integration tests
pytest tests/integration

# Coverage
pytest --cov=src --cov-report=html

Failure Analysis Guide

Test Failure Patterns

Root Cause Questions

1. Did the change modify the tested behavior?
2. Is the test using outdated data/fixtures?
3. Did environment configuration change?
4. Is there a dependency issue?

Coverage Targets

Anti-Patterns to Avoid

• Running tests without analyzing failures
• Skipping failed tests without documentation
• Low coverage on critical paths
• Not testing error scenarios

Usage

/regression-test
/regression-test [scope]

Example:

/regression-test
/regression-test backend
/regression-test src/frontend/components/

Coordination

• Test failures: Notify domain lead
• Cross-domain failures: Notify architect-lead
• Critical failures: Block merge
• Coverage drops: Require investigation