michaelschiemer/tests/e2e/livecomponent/README.md

LiveComponent E2E Tests

End-to-End tests for LiveComponent system functionality.

Prerequisites

E2E tests require:

• Running development server (npm run dev)
• Test components deployed at test URLs
• Playwright or similar E2E testing framework

Test Setup

Option 1: Playwright (Recommended)

npm install --save-dev @playwright/test
npx playwright install

Option 2: Puppeteer

npm install --save-dev puppeteer jest-puppeteer

Planned E2E Test Suites

Fragment Updates E2E Tests

File: FragmentUpdates.e2e.test.js

Test Scenarios:

1. Single Fragment Update

   • Load component with multiple fragments
   • Trigger action that updates single fragment
   • Verify only target fragment updated
   • Verify other fragments unchanged
   • Verify focus preserved

2. Multiple Fragment Updates

   • Trigger action with data-lc-fragments="frag1,frag2"
   • Verify both fragments updated
   • Verify unused fragments unchanged
   • Measure DOM mutation count

3. Fragment Update with Events

   • Update fragment that dispatches events
   • Verify event received by listeners
   • Verify event payload correct

4. Nested Fragment Updates

   • Update parent fragment containing child fragments
   • Verify proper nested patching
   • Verify no child components destroyed

5. Fragment Update Performance

   • Measure time for fragment update vs full render
   • Verify 70-95% DOM operation reduction
   • Measure bandwidth difference (60-90% reduction)

Example Implementation:

describe('Fragment Updates E2E', () => {
    beforeEach(async () => {
        await page.goto('http://localhost:5173/live-component/demo');
    });

    test('updates single fragment without affecting others', async () => {
        // Find component
        const component = await page.$('[data-live-component="user-stats:1"]');

        // Get initial fragment contents
        const initialHeader = await component.$eval(
            '[data-lc-fragment="header"]',
            el => el.textContent
        );
        const initialStats = await component.$eval(
            '[data-lc-fragment="stats"]',
            el => el.textContent
        );

        // Trigger action that updates only stats fragment
        await component.$eval(
            '[data-live-action="refreshStats"][data-lc-fragments="stats"]',
            btn => btn.click()
        );

        // Wait for update
        await page.waitForTimeout(100);

        // Verify stats updated
        const newStats = await component.$eval(
            '[data-lc-fragment="stats"]',
            el => el.textContent
        );
        expect(newStats).not.toBe(initialStats);

        // Verify header unchanged
        const newHeader = await component.$eval(
            '[data-lc-fragment="header"]',
            el => el.textContent
        );
        expect(newHeader).toBe(initialHeader);
    });

    test('preserves focus during fragment update', async () => {
        const input = await page.$('[data-live-component] input[name="search"]');

        // Focus input and type
        await input.focus();
        await input.type('test query');

        // Trigger fragment update
        await page.click('[data-live-action="search"][data-lc-fragments="results"]');
        await page.waitForTimeout(100);

        // Verify focus preserved
        const focusedElement = await page.evaluate(() => document.activeElement.name);
        expect(focusedElement).toBe('search');

        // Verify selection preserved
        const selectionStart = await input.evaluate(el => el.selectionStart);
        const selectionEnd = await input.evaluate(el => el.selectionEnd);
        expect(selectionStart).toBe(10);
        expect(selectionEnd).toBe(10);
    });
});

Multi-Component Batch Updates E2E Tests

File: BatchUpdates.e2e.test.js

Test Scenarios:

1. Automatic Batching

   • Queue multiple operations within 50ms window
   • Verify single HTTP request sent
   • Verify all components updated correctly

2. Manual Batch Execution

   • Execute batch with LiveComponent.executeBatch()
   • Verify all operations processed
   • Verify partial failures handled gracefully

3. Batch with Fragments

   • Batch multiple fragment updates
   • Verify fragments updated efficiently
   • Measure HTTP request reduction (60-80%)

4. Batch Performance

   • Compare batch vs individual requests
   • Measure latency reduction
   • Measure bandwidth reduction (~40%)

5. Batch Error Handling

   • Trigger batch with some invalid operations
   • Verify failed operations reported
   • Verify successful operations still applied
   • Verify error isolation (no cascade failures)

Example Implementation:

describe('Batch Updates E2E', () => {
    beforeEach(async () => {
        await page.goto('http://localhost:5173/live-component/batch-demo');
    });

    test('batches multiple operations automatically', async () => {
        // Monitor network requests
        const requests = [];
        page.on('request', req => {
            if (req.url().includes('/live-component/batch')) {
                requests.push(req);
            }
        });

        // Trigger multiple operations quickly
        await page.evaluate(() => {
            LiveComponent.queueBatchOperation({
                componentId: 'counter:1',
                method: 'increment'
            });
            LiveComponent.queueBatchOperation({
                componentId: 'counter:2',
                method: 'increment'
            });
            LiveComponent.queueBatchOperation({
                componentId: 'counter:3',
                method: 'increment'
            });
        });

        // Wait for batch to flush
        await page.waitForTimeout(100);

        // Verify single batch request
        expect(requests.length).toBe(1);

        // Verify all counters updated
        const counter1 = await page.$eval('[data-live-component="counter:1"]', el => el.textContent);
        const counter2 = await page.$eval('[data-live-component="counter:2"]', el => el.textContent);
        const counter3 = await page.$eval('[data-live-component="counter:3"]', el => el.textContent);

        expect(counter1).toContain('1');
        expect(counter2).toContain('1');
        expect(counter3).toContain('1');
    });

    test('handles partial batch failures gracefully', async () => {
        const result = await page.evaluate(async () => {
            return await LiveComponent.executeBatch([
                { componentId: 'valid:1', method: 'validAction' },
                { componentId: 'invalid:999', method: 'nonexistent' },
                { componentId: 'valid:2', method: 'validAction' }
            ], { autoApply: false });
        });

        expect(result.total_operations).toBe(3);
        expect(result.success_count).toBe(2);
        expect(result.failure_count).toBe(1);

        // Verify successful operations applied
        const valid1 = await page.$('[data-live-component="valid:1"]');
        const valid2 = await page.$('[data-live-component="valid:2"]');
        expect(valid1).not.toBeNull();
        expect(valid2).not.toBeNull();
    });
});

Running E2E Tests

Development

# Start dev server
npm run dev

# Run E2E tests in another terminal
npm run test:e2e

# Run with UI
npm run test:e2e:ui

# Debug mode
npm run test:e2e:debug

CI/CD

# Headless mode
npm run test:e2e:ci

Test Components

E2E tests require test components deployed at known URLs:

• /live-component/demo - Basic fragment update demo
• /live-component/batch-demo - Batch update demo
• /live-component/performance - Performance benchmark page

Performance Validation

E2E tests should validate the performance claims:

• Fragment Updates: 60-90% bandwidth reduction, 70-95% DOM operation reduction
• Request Batching: 60-80% request reduction, ~40% total bytes reduction

Visual Regression Testing

Consider adding visual regression tests using:

• Playwright's screenshot comparison
• Percy.io
• Chromatic

Accessibility Testing

E2E tests should include a11y checks:

• Focus management during updates
• ARIA live regions for dynamic content
• Keyboard navigation preservation

Browser Coverage

Test across:

• Chrome/Chromium
• Firefox
• Safari
• Edge

Future Enhancements

• Implement full Playwright test suite
• Add visual regression tests
• Add accessibility tests
• Add mobile device tests
• Add network throttling tests
• Add WebSocket/SSE update tests
• Add offline mode tests (PWA)