Introduction
In financial software testing, flaky tests are more than annoying — they’re dangerous. They waste CI time, block releases, and erode trust in your automation suite. Worse, they may cause your team to ignore real failures assuming it’s “just another flaky run.”
This article walks through why flaky tests happen in FinTech, and how to systematically detect, debug, and prevent them — especially across payment flows, KYC logic, tax calculations, and async APIs.
🔍 What Is a Flaky Test?
A flaky test is one that:
- Fails intermittently with no code changes
- Passes on rerun without fixing anything
- Has unclear logs or error messages
- Behaves differently across environments (local vs CI)
In FinTech, this often affects:
- UI-based tests tied to dashboards, approvals, or exports
- Async API updates (e.g., status changes from webhooks)
- Time-sensitive logic (scheduled payouts, token expiry)
🚨 Why Flaky Tests Are Risky in Financial QA
- They block PRs or pipelines at random
- They mask real defects when ignored
- They reduce confidence in automation as a release gate
- They can create false audit trails (e.g., test says “passed” but reality differs)
🧠 Common Causes of Flaky Tests in FinTech Apps
| Flaky Factor | Where It Appears |
|---|---|
| Async status updates | Payment status → “completed” not ready on reload |
| Poor selector strategy | UI tests tied to layout or text |
| Timing issues | Race conditions in API/UI layers |
| Data setup inconsistency | Missing test data, reused IDs |
| Third-party API latency | Delayed KYC or webhook events |
| Environment drift | Config mismatch between dev/staging/prod |
| Improper test teardown | Residual data polluting next test |
✅ Best Practices to Handle and Prevent Flaky Tests
1. 🧪 Use Stable Selectors and Timeouts in UI Tests
- Prefer
data-testidoraria-*attributes over CSS/xPath - Use
cy.get(...).should('be.visible')instead of fixed waits - Avoid
cy.wait(1000)unless truly needed — use dynamic waits
jsКопіюватиРедагуватиcy.get('[data-testid="txn-status"]').should('contain.text', 'Completed');
2. 🔁 Add Retry Logic for Eventual Consistency
If your system is eventually consistent (e.g., async transaction updates):
jsКопіюватиРедагуватиcy.retryUntil(() =>
cy.request('/payment/status').then(res => res.body.status === 'completed')
);
Or use Playwright’s built-in retries and assertions with timeout control.
3. 🧼 Reset State Before and After Tests
- Ensure test users, invoices, and payments are freshly created
- Clean up data using API or DB tools
- Isolate each test — don’t let one test’s data affect the next
Bonus: Tag critical data with a test run ID (e.g.,
QA-Run-0425) for easy cleanup.
4. 📊 Track Flaky Tests Over Time
Use dashboards or test reports to detect repeat offenders.
| Test Name | Flaky Rate | Last Flaky Run | Notes |
|---|---|---|---|
| testSubmitPayment.js | 12% | Apr 22 | Status update delay |
| testKYCUpload.js | 8% | Apr 21 | API retry logic missing |
| testRefundFlow.js | 2% | Apr 18 | UI element overlap |
Use tools like:
- Cypress Dashboard
- GitHub Actions annotations
- Custom Airtable / Notion QA logs
- TestRail tags (Flaky / Needs Review)
5. 🚦 Categorize and Quarantine Problematic Tests
Tag tests:
- 🟢 Reliable
- 🟡 Needs Retry
- 🔴 Quarantine / Do Not Block CI
For CI pipelines:
- Run all tests, but only block releases on reliable suites
- Run flaky tests separately and alert QA (not fail build)
6. 🧰 Use Tools That Support Debugging
- Playwright traces (video + DOM snapshot playback)
- Cypress screenshots/videos on failure
- Sentry integration for API error logs
- Logs from Webhook or Kafka consumers
Combine visual debugging with log tracing to pinpoint async failure sources.
7. 🧪 Test Critical Flows at the API Layer First
UI tests are more likely to be flaky — validate critical backend logic through API tests whenever possible:
- Create payment via API → assert DB/payment log
- Mark invoice approved → assert next status via
/invoices/:id - Bypass unstable UI steps unless you’re explicitly testing them
Final Thoughts
Flaky tests aren’t just frustrating — they’re a sign your test system needs reinforcement. In FinTech, they can cause missed defects or delayed releases in sensitive, high-risk features.
The fix isn’t just deleting them — it’s:
- Tracking causes
- Retrying responsibly
- Isolating brittle areas
- Strengthening environment control and data hygiene
✅ Flaky Test Tracker Template
Track, categorize, and prioritize flaky tests in your FinTech QA suite.
Use this in Google Sheets, Airtable, or Notion.
| Test Name | Module / Feature | Flaky Rate (%) | Last Failed Run | Suspected Cause | Fix Status | CI Blocker? | Assigned To | Notes |
|---|---|---|---|---|---|---|---|---|
| testSubmitPayment | Payments | 15% | Apr 22 | Delayed payment status update | Needs Retry | ❌ No | QA_Marina | Add polling or webhook mock |
| testKYCUpload | KYC | 10% | Apr 21 | API timeout | In Progress | ✅ Yes | QA_Andrii | Use MSW to simulate failure scenarios |
| testInvoiceExport | Invoices | 5% | Apr 20 | UI render delay | Retested | ❌ No | QA_Taras | Delay related to PDF generator timing |
| testRefundFlow | Payments | 8% | Apr 18 | Modal not loaded fully | Investigate | ❌ No | QA_Oleh | Potential z-index overlay interference |
| testRolePermissions | Admin Dashboard | 3% | Apr 17 | User state desync | Fixed | ❌ No | QA_Nataliia | Added forced logout between sessions |
Suggested filters:
- Sort by highest flaky rate
- Group by module
- Filter by blocker status
- Highlight stale “Investigate” cases
⚙️ CI Strategy Guide for FinTech Test Stability
Use this to improve automation confidence across your build pipeline.
✅ 1. Split Tests by Reliability
- Reliable suite → Run on every PR (CI blocking)
- Flaky/long-running suite → Run nightly or post-merge
- Use test tags or folders:
@critical,@non-blocking,@quarantined
✅ 2. Track & Isolate Failures
- Integrate test dashboards (e.g., Cypress Cloud, Playwright Trace Viewer)
- Auto-log flaky tests into your tracker after 2+ consecutive failures
- Post alerts to Slack or Jira (not failing CI) for flaky-only jobs
✅ 3. Add Stability Checks to Pre-Merge Workflows
- Enforce test retries (e.g., Playwright
--retries=2, Cypress config retries) - Fail builds only if:
- Critical test fails
- Failure repeats after all retries
✅ 4. Run Full Regression Nightly
- Schedule all tests (including flagged flaky tests) every night or early morning
- Run across browsers (Chrome, Firefox) and devices (if applicable)
- Store screenshots/videos of all failures in CI artifacts for QA review
✅ 5. Control Environment Variables Per Pipeline
- Use
.env.staging,.env.qa, or GitHub Actions secrets to control:- Base URLs
- API keys
- Timeout configs
- Feature flags
✅ 6. Stabilize Data and Cleanup
- Run DB cleanup or API reset hooks after every test run
- Tag test data by run ID for easy purging
- Use test fixtures or seeding tools with deterministic values