SmartUI Visual Regression Skill
Core Patterns
Playwright + SmartUI SDK
javascriptconst { chromium } = require('playwright'); const { smartuiSnapshot } = require('@lambdatest/smartui-cli'); (async () => { const browser = await chromium.launch(); const page = await browser.newPage(); await page.goto('https://example.com'); await smartuiSnapshot(page, 'Homepage'); await page.goto('https://example.com/login'); await smartuiSnapshot(page, 'Login Page'); await browser.close(); })();
Selenium + SmartUI
java// Take SmartUI screenshot ((JavascriptExecutor) driver).executeScript( "smartui.takeScreenshot=Login Page" );
CLI Execution
bash# Install npm install @lambdatest/smartui-cli@latest --save-dev # Configure npx smartui config:create smartui.config.json # Execute npx smartui exec -- node test.js # or with Playwright npx smartui exec -- npx playwright test
smartui.config.json
json{ "web": { "browsers": ["chrome", "firefox", "safari"], "viewports": [[1920, 1080], [1366, 768], [375, 812]] }, "waitForPageRender": 5000, "waitForTimeout": 1000 }
SmartUI with Storybook
bashnpx smartui storybook http://localhost:6006 --config smartui.config.json
Approval Workflow
- First run creates baseline screenshots
- Subsequent runs compare against baseline
- Differences highlighted in dashboard
- Approve/reject changes in LambdaTest SmartUI dashboard
- Approved screenshots become new baseline
Anti-Patterns
| Bad | Good | Why |
|---|---|---|
| No viewport config | Multiple viewports | Responsive issues |
| No wait for render | waitForPageRender | Incomplete screenshots |
| Screenshot everything | Key pages/components | Noise reduction |
| No approval process | Review diffs in dashboard | Catch regressions |
Cloud Authentication
Set environment variables:
bashexport PROJECT_TOKEN="your-smartui-project-token" # From SmartUI dashboard export LT_USERNAME="your-username" # For Selenium/Playwright cloud export LT_ACCESS_KEY="your-access-key" # For Selenium/Playwright cloud
CLI approach (uses PROJECT_TOKEN):
bashnpx smartui exec -- npx playwright test
Selenium Cloud approach (uses LT_USERNAME/LT_ACCESS_KEY):
java// Capabilities include SmartUI options HashMap<String, Object> ltOptions = new HashMap<>(); ltOptions.put("user", System.getenv("LT_USERNAME")); ltOptions.put("accessKey", System.getenv("LT_ACCESS_KEY")); ltOptions.put("build", "SmartUI Build"); ltOptions.put("smartUI.project", "My SmartUI Project"); ChromeOptions options = new ChromeOptions(); options.setCapability("LT:Options", ltOptions); WebDriver driver = new RemoteWebDriver( new URL("https://hub.lambdatest.com/wd/hub"), options);
Quick Reference
| Task | Command |
|---|---|
| Install | npm install @lambdatest/smartui-cli@latest |
| Init config | npx smartui config:create smartui.config.json |
| Run | npx smartui exec -- <test command> |
| Storybook | npx smartui storybook <url> |
| Dashboard | https://smartui.lambdatest.com |
Deep Patterns
For advanced patterns, debugging guides, CI/CD integration, and best practices,
see reference/playbook.md.


