--- name: playwright-regression-testing description: 'Automated regression testing strategy and best practices using Playwright with TypeScript. Use when asked to plan, organize, select, execute, or optimize regression test suites for web applications. Covers change-based and risk-based test selection, test tagging and prioritization, parallel execution, sharding, CI/CD pipeline integration with GitHub Actions, flaky test management, suite health monitoring, and regression types (corrective, progressive, selective, complete). Keywords: regression testing, test selection, smoke tests, test suite optimization, CI pipeline, flaky tests, test sharding, impact analysis, git diff.' --- # Playwright Regression Testing (TypeScript) Strategy and best practices for automated regression testing of web applications using Playwright with TypeScript. > **Activation:** This skill is triggered when working with regression test strategy, test suite selection, test prioritization, CI/CD pipeline testing, flaky test management, test sharding, or optimizing test execution for web applications using Playwright. ## When to Use This Skill - **Plan regression suites** with risk-based and change-based test selection - **Organize tests** into tiers (smoke, sanity, selective, full regression) - **Optimize execution** with parallelization, sharding, and time-budget strategies - **Integrate with CI/CD** using GitHub Actions pipelines - **Manage flaky tests** with quarantine, retry policies, and root cause tracking - **Monitor suite health** with execution time, flake rate, and detection metrics - **Select tests after changes** using git diff analysis and impact mapping ## Prerequisites | Requirement | Details | | -------------- | ---------------------------------------- | | Node.js | v18+ recommended | | Playwright | `@playwright/test` package | | TypeScript | `typescript` configured in project | | Browsers | Installed via `npx playwright install` | | Git | Required for change-based test selection | | GitHub Actions | Recommended CI/CD platform | --- ## Quick Reference ### Tier Model ``` Tier 0 — Smoke (< 2 min) → Critical path, runs on every commit Tier 1 — Sanity (< 10 min) → Core features, runs on every PR Tier 2 — Selective (< 30 min) → Change-based + risk-based, runs on merge Tier 3 — Full (< 60 min) → Complete regression, runs nightly/pre-release ``` ### Regression Types | Type | When | Scope | | --------------- | ---------------------------------------- | ---------------------------------- | | **Corrective** | No app code changed (infra, config, env) | Full suite to verify nothing broke | | **Progressive** | New features added | Existing tests + new feature tests | | **Selective** | Specific code changes | Changed modules + dependent tests | | **Complete** | Major refactor, release candidate | Run everything across all projects | ### Tag Taxonomy | Tag | Purpose | Tier | | ------------- | -------------------------------- | ------------- | | `@smoke` | Critical path, must always pass | 0 | | `@sanity` | Core feature verification | 1 | | `@regression` | Standard regression coverage | 2-3 | | `@critical` | Revenue/business-critical flows | 0-1 | | `@slow` | Tests exceeding 30 seconds | 3 | | `@quarantine` | Known flaky, under investigation | Skipped in CI | | `@a11y` | Accessibility checks | 2 | ### CLI Quick Reference | Command | Description | | ----------------------------------------------- | ------------------------ | | `npx playwright test --grep @smoke` | Run smoke tier only | | `npx playwright test --grep @regression` | Run regression suite | | `npx playwright test --grep-invert @quarantine` | Skip quarantined tests | | `npx playwright test --shard=1/4` | Run shard 1 of 4 | | `npx playwright test --last-failed` | Re-run only failed tests | --- ## Common Rationalizations > Common shortcuts and "good enough" excuses that erode test quality — and the reality behind each. | Rationalization | Reality | | -------------------------------------------------- | ------------------------------------------------------------------------------------------------------- | | "Run all tests every time" | Change-based test selection reduces CI time 60-80%. Run the full suite nightly, not every commit. | | "Flaky tests are normal" | Flaky tests erode trust in the entire suite. Quarantine, investigate, and fix them. | | "Regression testing is just re-running everything" | Strategic selection (risk-based, change-based) catches more defects in less time than brute-force runs. | | "Test sharding is premature optimization" | Parallel sharding cuts CI time linearly with workers. Start with 4 shards from day one. | | "Smoke tests cover regression" | Smoke tests verify health; regression tests verify behavior. They serve different purposes. | | "Tagging tests is busywork" | Tags enable selective execution, prioritization, and suite analysis. Untagged suites are unmanageable. | --- ## References | Document | Content | | ---------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [Regression Strategy](./references/regression-strategy.md) | Tier definitions, test selection (change-based, risk-based, historical, time-budget), directory layout, tagging, naming conventions, Playwright best practices, example test | | [CI/CD Integration](./references/ci-cd-integration.md) | GitHub Actions tiered pipeline, sharding, merge reports, Playwright config, performance optimization, CLI reference | | [Flaky Management](./references/flaky-management.md) | Retry policies, quarantine strategies, detection checklist, suite health metrics, troubleshooting | --- ## Verification After completing this skill's workflow, confirm: - [ ] **Regression suite covers critical paths** — All priority-1 user flows have regression tests - [ ] **Smoke test subset identified** — Tagged `@smoke` tests run in under 2 minutes - [ ] **No test duplication** — Each scenario tested exactly once at the appropriate level - [ ] **Test isolation verified** — Running tests in random order produces same results as sequential - [ ] **Flaky test baseline established** — All tests pass 5/5 consecutive runs - [ ] **CI pipeline configured** — GitHub Actions workflow runs regression on schedule - [ ] **Allure or HTML report generated** — Test results available in human-readable format