test: Add performance tests to Playwright (#17574)

packages/testing/playwright/utils/performance-helper.ts

@@ -0,0 +1,30 @@
+import type { Page } from '@playwright/test';
+
+export async function measurePerformance(
+	page: Page,
+	actionName: string,
+	actionFn: () => Promise<void>,
+): Promise<number> {
+	// Mark start
+	await page.evaluate((name) => performance.mark(`${name}-start`), actionName);
+
+	// Execute action
+	await actionFn();
+
+	// Mark end and get duration
+	return await page.evaluate((name) => {
+		performance.mark(`${name}-end`);
+		performance.measure(name, `${name}-start`, `${name}-end`);
+		const measure = performance.getEntriesByName(name)[0] as PerformanceMeasure;
+		return measure.duration;
+	}, actionName);
+}
+
+export async function getAllPerformanceMetrics(page: Page) {
+	return await page.evaluate(() => {
+		const metrics: Record<string, number> = {};
+		const measures = performance.getEntriesByType('measure') as PerformanceMeasure[];
+		measures.forEach((m) => (metrics[m.name] = m.duration));
+		return metrics;
+	});
+}