Designing a resilient test suite for a high-concurrency, real-time dashboard

🔥 Playwright Flakiness Killer:
Financial dashboard tests fail because transient "Processing..." flashes and WebSocket noise mask the final stable state. How do you assert State D without false positives?

📌 Problem Statement
High-concurrency trading dashboard. State A → Action → Transient B/C (errors/partial updates) → State D. Timing unpredictable. Background WebSocket fires irrelevant updates. Basic waits fail.

💡 Solution & Code Walkthrough
Use expect.poll() with custom timeout + page.route() to mute noise. Assert final state while ignoring intermediate flashes.

// Assert final State D while ignoring transient B/C states
await expect.poll(async () => {
  const status = await page.locator('#order-status').textContent();
  const errors = await page.locator('.transient-error').count();
  return { status, errors };
}, { timeout: 30000 }).toBe({ status: 'Success', errors: 0 });

Mute WebSocket noise:

// Mute irrelevant background WebSocket noise during critical action
await page.route('**/ws/feed', route => route.abort());

🔑 Key Takeaways
• expect.poll() retries until condition met or timeout
• Assert absence of transient errors alongside final state
• Route/abort irrelevant WebSocket events during critical window
• Never use brittle waitForSelector for state transitions

❓ Quick Summary Q&A
Q: Why not waitForSelector? A: It catches intermediate states, causing flakiness.
Q: How to handle WebSocket noise? A: Intercept and abort non-critical feeds during the action window.

TAGS: playwright, testing, automation, resilience, websocket

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