end-to-end-testing

End-to-End Testing

End-to-end tests are the most valuable and the most expensive tests — they prove a real user journey works across the whole stack, and they break for unrelated reasons if written carelessly. The discipline: few but critical journeys, semantic locators, zero hard sleeps, and isolated data. A flaky end-to-end suite is worse than none — teams learn to ignore red.

Lint Playwright specs for flakiness anti-patterns: python3 scripts/lint_e2e.py tests/**/*.spec.ts

Cover journeys, not units (it's the tip of the pyramid)

End-to-end tests are slow and broad — reserve them for the handful of journeys that, if broken, mean the product is down: sign up → log in, add to cart → checkout, the core create→read→update path. Everything else (edge cases, error states, validation) is cheaper and more reliable as unit/integration tests. Which test type for a given change is owned by testing-strategy — this skill is how to write the end-to-end ones well.

Playwright — locators + auto-wait (web)

// Wrong — brittle selector + a hard sleep = flaky and slow
await page.waitForTimeout(3000);
await page.click(".btn-primary.css-1x2y3z");      // generated class, breaks on rebuild

// Correct — semantic locator + auto-waiting assertion
await page.getByRole("button", { name: "Sign in" }).click();   // waits for actionable
await expect(page.getByText("Welcome")).toBeVisible();          // retries until true or times out

Playwright auto-waits for elements to be actionable — getByRole/getByLabel/ getByText plus web-first expect assertions retry automatically. A waitForTimeout is always wrong: either too short (flaky) or too long (slow). Prefer role/label/text locators (they double as accessibility checks — see a11y) over CSS/XPath. Detail → references/playwright.md.

Maestro — flows for mobile

# flows/login.yaml
appId: com.example.app
---
- launchApp
- tapOn: "Email"
- inputText: "[email protected]"
- tapOn: "Sign in"
- assertVisible: "Welcome"