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Regression Testing

proffesor-for-testing/agentic-qe

  • 284 installs
  • 433 repo stars
  • Updated August 4, 2026
  • proffesor-for-testing/agentic-qe

regression-testing is a Claude skill that builds and maintains regression test suites catching unintended breakage after refactors, dependency upgrades, or feature additions for developers protecting critical user journe

About

regression-testing is a Claude skill from proffesor-for-testing/agentic-qe focused on building durable regression suites that protect critical user journeys. The skill helps developers identify high-risk flows, prioritize coverage after refactors or dependency bumps, and structure repeatable test runs that catch unintended breakage before release. Developers reach for regression-testing when a codebase change could silently break checkout, auth, onboarding, or other revenue-critical paths and they need a systematic suite rather than ad hoc smoke checks.

  • Risk-based suite prioritization
  • Smoke versus full regression tiers
  • Flake detection and quarantine
  • Change-impact mapping
  • Release gate criteria

Regression Testing by the numbers

  • 284 all-time installs (skills.sh)
  • +7 installs in the week ending Aug 4, 2026 (Skillselion tracking)
  • Ranked #724 of 2,153 Testing & QA skills by installs in the Skillselion catalog
  • Data as of Aug 5, 2026 (Skillselion catalog sync)
npx skills add https://github.com/proffesor-for-testing/agentic-qe --skill regression-testing

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Listed on Skillselion
Installs284
repo stars★ 433
Last updatedAugust 4, 2026
Repositoryproffesor-for-testing/agentic-qe ↗

How do you build regression tests for critical flows?

Build and maintain regression suites that catch unintended breakage after refactors, dependency upgrades, or feature additions across critical user journeys.

Who is it for?

QA-minded developers maintaining suites after large refactors, library upgrades, or frequent feature shipping.

Skip if: Greenfield projects with no production traffic yet that only need initial unit test scaffolding.

When should I use this skill?

A developer mentions regression tests, post-refactor breakage, dependency upgrade validation, or protecting critical user journeys.

What you get

Regression test suite, prioritized journey coverage map, and repeatable CI execution plan

  • regression test suite
  • journey coverage matrix

Files

SKILL.mdMarkdownGitHub ↗

Regression Testing

<default_to_action> When verifying changes don't break existing functionality: 1. ANALYZE what changed (git diff, impact analysis) 2. SELECT tests based on change + risk (not everything) 3. RUN in priority order (smoke → selective → full) 4. OPTIMIZE execution (parallel, sharding) 5. MONITOR suite health (flakiness, execution time)

Quick Regression Strategy:

  • Per-commit: Smoke + changed code tests (5-10 min)
  • Nightly: Extended regression (30-60 min)
  • Pre-release: Full regression (2-4 hours)

Critical Success Factors:

  • Smart selection catches 90% of regressions in 10% of time
  • Flaky tests waste more time than they save
  • Every production bug becomes a regression test

</default_to_action>

Quick Reference Card

When to Use

  • After any code change
  • Before release
  • After dependency updates
  • After environment changes

Test Selection Strategies

StrategyHowReduction
Change-basedGit diff analysis70-90%
Risk-basedPriority by impact50-70%
HistoricalFrequently failing40-60%
Time-budgetFixed time windowVariable

---

Change-Based Test Selection

// Analyze changed files and select impacted tests
function selectTests(changedFiles: string[]): string[] {
  const testsToRun = new Set<string>();

  for (const file of changedFiles) {
    // Direct tests
    testsToRun.add(`${file.replace('.ts', '.test.ts')}`);

    // Dependent tests (via coverage mapping)
    const dependentTests = testCoverage[file] || [];
    dependentTests.forEach(t => testsToRun.add(t));
  }

  return Array.from(testsToRun);
}

// Example: payment.ts changed
// Runs: payment.test.ts, checkout.integration.test.ts, e2e/purchase.test.ts

---

CI/CD Integration

# .github/workflows/regression.yml
jobs:
  quick-regression:
    runs-on: ubuntu-latest
    timeout-minutes: 15
    steps:
      - name: Analyze changes
        id: changes
        uses: dorny/paths-filter@v2
        with:
          filters: |
            payment:
              - 'src/payment/**'
            auth:
              - 'src/auth/**'

      - name: Run affected tests
        run: npm run test:affected

      - name: Smoke tests (always)
        run: npm run test:smoke

  nightly-regression:
    if: github.event_name == 'schedule'
    timeout-minutes: 120
    steps:
      - run: npm test -- --coverage

---

Agent-Driven Regression

// Smart test selection
await Task("Regression Analysis", {
  pr: 1234,
  strategy: 'change-based-with-risk',
  timeBudget: '15min'
}, "qe-regression-risk-analyzer");

// Returns:
// {
//   mustRun: ['payment.test.ts', 'checkout.integration.test.ts'],
//   shouldRun: ['order.test.ts'],
//   canSkip: ['profile.test.ts', 'search.test.ts'],
//   estimatedTime: '12 min',
//   riskCoverage: 0.94
// }

// Generate regression test from production bug
await Task("Bug Regression Test", {
  bug: { id: 'BUG-567', description: 'Checkout fails > 100 items' },
  preventRecurrence: true
}, "qe-test-generator");

---

Agent Coordination Hints

Memory Namespace

aqe/regression-testing/
├── test-selection/*     - Impact analysis results
├── suite-health/*       - Flakiness, timing trends
├── coverage-maps/*      - Test-to-code mapping
└── bug-regressions/*    - Tests from production bugs

Fleet Coordination

const regressionFleet = await FleetManager.coordinate({
  strategy: 'comprehensive-regression',
  agents: [
    'qe-regression-risk-analyzer',  // Analyze changes, select tests
    'qe-test-executor',             // Execute selected tests
    'qe-coverage-analyzer',         // Analyze coverage gaps
    'qe-quality-gate'               // Go/no-go decision
  ],
  topology: 'sequential'
});

---

Related Skills

  • risk-based-testing - Risk-based prioritization
  • test-automation-strategy - Automation pyramid
  • continuous-testing-shift-left - CI/CD integration

---

Remember

With Agents: qe-regression-risk-analyzer provides intelligent test selection achieving 90% defect detection in 10% of execution time. Agents generate regression tests from production bugs automatically.

Skill Composition

  • Test failing? → Use /test-failure-investigator to diagnose root cause
  • File a bug → Use /bug-reporting-excellence for proper bug reporting
  • Test selection → Use /risk-based-testing for risk-based prioritization

Gotchas

  • Agent defaults to "run everything" despite being told to select — explicitly constrain with --affected or file list
  • Change-based selection misses transitive dependencies — a model change can break a controller test 3 hops away
  • Flaky tests in regression suites erode trust faster than missing tests — quarantine immediately, don't skip
  • Agent may report "0 regressions" when tests simply weren't run — verify test count in output, not just pass/fail
  • Running full regression in containers often OOMs — use --workers=2 and --shard for CI environments

Related skills

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FAQ

What problems does regression-testing address?

regression-testing helps developers catch unintended breakage after refactors, dependency upgrades, or new features. The skill focuses on maintaining suites that cover critical user journeys instead of only adding one-off tests.

When should regression-testing run in CI?

regression-testing designs suites meant to run on every meaningful code change or pre-release pipeline. The skill prioritizes high-risk flows so CI catches regressions before they reach production users.

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