fabrico-e2e-testing

name	fabrico-e2e-testing
description	E2E testing patterns, verification procedures, and CI readiness checklists using Playwright. Use for writing, debugging, or reviewing end-to-end tests, fixing flaky tests, creating Page Objects, mocking external APIs.

E2E Testing Patterns & Practices

Page Object Pattern

export class FeaturePage {
  constructor(readonly page: Page) {}
  get submitBtn() {
    return this.page.getByRole('button', { name: 'Submit' });
  }
  async navigate() { await this.page.goto('/feature'); }
}

Test Structure

test('should [behavior] when [condition]', async ({ page }) => {
  const id = `test-${Date.now()}-${test.info().parallelIndex}`;
  // Arrange → Act → Assert
});

Mocking (external APIs only)

await page.route('**/api/external/**', route => route.fulfill({ status: 200, body: '{}' }));

Verification Loop

RUN → FAIL? → DEBUG (browser_snapshot via the playwright MCP server) → FIX → REPEAT

When debugging, capture the page state with the playwright MCP server (tools mcp__playwright__*, e.g. mcp__playwright__browser_snapshot) to inspect the accessibility tree and locate failing elements.

Rule	Limit
Max per test	5 iterations → test.fixme()
Max per suite	15 iterations → stop
Flaky detection	3 pass/fail mix → investigate
Stability	3+ consecutive passes required
App bug	Mark test.fixme('BUG: desc')

Error Recovery

Error	Action
Timeout	Increase once → check selector → check if element renders
Element not found	Alternative locator → check DOM → verify page loaded
Network	Retry → consider mock → verify backend
Flaky	Explicit waits → check race conditions → run 5x
App bug	Mark test.fixme('BUG: desc') - test is skipped; CI usually still passes unless skipped tests fail the build

CI Readiness Checklist

• Passes headless: npx playwright test --headed=false
• Uses process.env.BASE_URL
• No hardcoded credentials
• Explicit viewport

Quick Reference

Always: accessible locators, unique test data, 3+ passes, mock external APIs Never: waitForTimeout(), CSS selectors, test interdependencies, hardcoded creds