Optimistic UI Updates | QAJourney Playground

Test scenario

Both actions below hit a real backend endpoint with a genuine delay and a genuine 35% failure rate, not a scripted timer. The failure is never guaranteed, which is the point.

Test goals

Playwright snippet

await page.route('**/optimistic-action.php', route => route.abort());
await page.click('[data-testid="like-btn"]');
await expect(page.locator('[data-testid="like-btn"]'))
  .not.toHaveClass(/liked/);

Related reading

The reasoning behind this module

Why this bug passes every test you have Hybrid QA methodology Happy path vs sad path testing

Automate this with

Playwright — real-world QA

Mode

Optimistic updates the UI immediately. Pessimistic waits for the real response first.

Like button

Rapid double-click test

Click twice as fast as you can. Watch whether the count ends up where you expect.

Items added: 0

Export:

Bug title Steps to reproduce Expected result Actual result

Severity

Priority

Environment Additional notes

Export:

Select test type, framework, and output. Context is pre-filled for this module. Copy the prompt into any AI tool.

Test type

Manual

Automation

Regression

Smoke

E2E

API

Framework

Cypress

Playwright

Selenium

Postman

None / Generic

Output type

Test case generation

Bug report

Regression suite

Edge case discovery

Acceptance criteria review

Context (pre-filled — edit as needed)

Your prompt

Test notes & issues