E2e Testing Agent Skill

E2E Testing Skill (Playwright)

Playwright-based E2E testing across four phases: Scaffold, Build, Run, Validate. Each phase produces a saved artifact and must pass its gate before the next phase begins.

Reference Loading Table

| Signal | Load These Files | Why |

|---|---|---|

| async, Promise.all, race condition, waitForTimeout, fixture teardown | async.md | Routes to the matching deep reference |

| auth, login, storageState, OAuth, SSO, JWT, RBAC, multi-role, session expiry | auth.md | Routes to the matching deep reference |

| config, playwright.config.ts, POM, data-testid, CI/CD workflow | templates.md | Routes to the matching deep reference |

| error, timeout, tsc fail, locator, fill, missing JSON | errors.md | Routes to the matching deep reference |

| POM examples, waiting, multi-browser, shared auth session | playwright-patterns.md | Routes to the matching deep reference |

| Web3, MetaMask, wallet, addInitScript | wallet-testing.md | Routes to the matching deep reference |

| payment, financial, production skip, blockchain | financial-flows.md | Routes to the matching deep reference |

| flaky, intermittent, repeat-each, retries, quarantine | flakiness-triage.md | Routes to the matching deep reference |

Instructions

PHASE 1: SCAFFOLD

Goal: Verify Playwright is installed, create the directory structure, and generate playwright.config.ts.

Actions:

• Check if @playwright/test is installed: npx playwright --version. If not, run npm install -D @playwright/test and npx playwright install.
• Create directory structure:

   tests/
     e2e/
       auth/
       features/
       api/
   pages/          <- POM classes live here
   artifacts/
     screenshots/
     traces/
     videos/

• Write playwright.config.ts using the template in references/templates.md. The config bakes in failure diagnostics by default: screenshot: 'only-on-failure', trace: 'on-first-retry', and video: 'retain-on-failure' so that every failure produces actionable artifacts without manual setup. CI retries (retries: process.env.CI ? 2 : 0) absorb transient infrastructure flakiness without masking real bugs.
• Confirm playwright.config.ts is valid TypeScript: npx tsc --noEmit. Run this deterministic check before any subjective assessment of the config -- compiler errors are facts, opinions are not.

Artifact: playwright.config.ts + tests/e2e/ directory structure.

Gate: playwright.config.ts exists AND tests/e2e/ directory exists. If either is missing, do not proceed to Phase 2 -- diagnose and fix.

See references/templates.md for the full playwright.config.ts template and multi-browser matrix rationale.

PHASE 2: BUILD

Goal: Write POM classes for target feature areas, then write spec files that use those POMs.

Every page or feature area gets a typed Page Object class. Spec files never contain inline locators -- all selectors live in the POM. This separation means a selector change is a one-line POM edit, not a grep-and-replace across dozens of specs.

Actions:

• Identify the feature areas under test (auth, checkout, dashboard, etc.).
• For each area, create a POM class in pages/ (see POM Pattern in references/templates.md). All locators must use data-testid attributes via page.getByTestId(). CSS selectors (page.locator('.btn-primary')) break silently when styles change. XPath breaks on DOM restructuring. Text matching (page.locator('text=Submit')) breaks on copy changes. data-testid is a testing contract that survives all three.
• Write spec files in tests/e2e/<area>/ using the POMs.
• Run npx tsc --noEmit to verify all files compile.
• Fix any TypeScript errors before proceeding.

Artifact: tests/e2e/**/*.spec.ts files + pages/*.ts POM classes, all compiling cleanly.

Gate: At least one .spec.ts exists under tests/e2e/ AND npx tsc --noEmit exits 0. If compile fails, fix errors -- do not proceed to Phase 3 with broken TypeScript.

See references/templates.md for the POM Pattern, data-testid convention, and waiting/timing rules.

PHASE 3: RUN

Goal: Execute the test suite, capture the results JSON, and identify any failing or flaky tests.

Actions:

• Ensure the application under test is running (or document the BASE_URL required).
• Run the full suite with JSON reporter configured in playwright.config.ts:

   npx playwright test

• If any tests fail, run them in isolation with --repeat-each=5 to distinguish flaky from consistently failing:

   npx playwright test tests/e2e/auth/login.spec.ts --repeat-each=5

• Quarantine confirmed flaky tests with test.fixme(). Never delete a failing test -- deleted tests leave silent coverage gaps. Quarantined tests are visible debt with tracking references:

   test.fixme('flaky: login redirects intermittently', async ({ page }) => {
     // TODO: #123 -- investigate race condition with auth cookie
     ...
   });

• Use test.skip() only for conditional environment guards (e.g., "skip on WebKit"), not for sweeping failures under the rug.

Artifact: playwright-results.json (presence is the gate -- pass rate is not).

Gate: playwright-results.json exists at the project root. The file must contain valid JSON. Pass rate does not block Phase 4 -- reporting on failures is Phase 4's job.

See references/templates.md for the full Flaky Test Quarantine Protocol.

PHASE 4: VALIDATE

Goal: Deterministic checks on test output, then structured report generation.

Actions:

• Deterministic checks first -- run these before any LLM summary because compiler output and JSON parsing are facts, not opinions:
• playwright-results.json exists and parses as valid JSON.
• Extract counts: python3 -c "import json,sys; d=json.load(open('playwright-results.json')); print(d.get('stats', d))"
• Identify all unexpected (failed) and flaky result entries.
• LLM triage (only after deterministic checks pass):
• For each failed test, identify whether it is: (a) a broken assertion, (b) a selector mismatch, (c) a timing/async issue, or (d) an application bug.
• Categorize flaky tests for quarantine vs. fix.
• Write e2e-report.md using the report template in references/templates.md.

Artifact: e2e-report.md.

Gate: e2e-report.md exists. Skill is complete only when this file is written.

See references/templates.md for the e2e-report.md template and the GitHub Actions CI/CD workflow template.

Error Handling

See references/errors.md for the symptom/cause/fix matrix covering tsc failures, CI-only flakes, missing results JSON, locator timeouts, fill-vs-clear bugs, and DOM ordering issues.

References

| Signal / Task Type | Load This Reference |

|--------------------|---------------------|

| async, Promise.all, race condition, waitForTimeout, fixture teardown | async.md |

| auth, login, storageState, OAuth, SSO, JWT, RBAC, multi-role, session expiry | auth.md |

| config, playwright.config.ts, POM, data-testid, CI/CD workflow | templates.md |

| error, timeout, tsc fail, locator, fill, missing JSON | errors.md |

| POM examples, waiting, multi-browser, shared auth session | playwright-patterns.md |

| Web3, MetaMask, wallet, addInitScript | wallet-testing.md |

| payment, financial, production skip, blockchain | financial-flows.md |

| flaky, intermittent, repeat-each, retries, quarantine | flakiness-triage.md |

• ADR-107 -- Decision record for this skill
• Playwright docs -- Official API reference