Analytics & Tracking Testing

If tracking is wrong, every product decision built on it is wrong. Treat the tracking plan as a contract and test it like an API.

1. Tracking plan (source of truth)

event name · trigger · properties (name/type/enum/required) · owner · destinations. Naming: object_action snake_case (checkout_started). Version it in git; generate JSON Schema for validation (Segment Protocols, Avo, Amplitude Data).

2. Verify in the browser

// Console: watch the dataLayer
window.dataLayer.push = new Proxy(window.dataLayer.push, { apply(t, s, a){ console.log('DL', JSON.stringify(a[0])); return Reflect.apply(t, s, a);} });

• GTM Preview / Tag Assistant; GA4 DebugView (?debug_mode=1); Segment Debugger; Meta Pixel Helper; chrome://net-export or DevTools Network filter collect|g/collect|track.
• Automate: Playwright intercepts requests and asserts payloads.

const hits: any[] = [];
page.on('request', r => { if (/google-analytics\.com\/g\/collect|\/v1\/track/.test(r.url())) hits.push(r.postData() ?? r.url()); });
await page.getByRole('button',{name:'Add to cart'}).click();
await expect.poll(() => hits.some(h => h.includes('add_to_cart'))).toBeTruthy();

3. What to assert

4. Parity (weekly automated)

Compare analytics revenue/orders/signups vs backend DB for the same window. Expect small drift (ad-blockers ~5–15%); alert when > threshold or trend changes after a release.

5. Regression net

Contract test each event schema in CI (JSON Schema + example payload from E2E); block deploys that rename events or drop required props; release checklist step "tracking verified".

Related

e2e-testing, payment-ecommerce-testing, compliance-testing, seo-testing, observability-testing