test: Add integration test for isolateTrace functionality

Add node integration test to verify that withMonitor calls with
isolateTrace: true generate different trace IDs, confirming trace
isolation works as expected.

Author: naaa760

dev-packages/node-integration-tests/suites/public-api/withMonitor/scenario.ts

@@ -0,0 +1,28 @@
+import { withMonitor } from '@sentry/node';
+
+export async function run(): Promise<void> {
+  // First withMonitor call without isolateTrace (should share trace)
+  await withMonitor('cron-job-1', async () => {
+    // Simulate some work
+    await new Promise<void>((resolve) => {
+      setTimeout(() => {
+        resolve();
+      }, 100);
+    });
+  }, {
+    schedule: { type: 'crontab', value: '* * * * *' }
+  });
+
+  // Second withMonitor call with isolateTrace (should have different trace)
+  await withMonitor('cron-job-2', async () => {
+    // Simulate some work
+    await new Promise<void>((resolve) => {
+      setTimeout(() => {
+        resolve();
+      }, 100);
+    });
+  }, {
+    schedule: { type: 'crontab', value: '* * * * *' },
+    isolateTrace: true
+  });
+}

dev-packages/node-integration-tests/suites/public-api/withMonitor/test.ts

@@ -0,0 +1,19 @@
+import { expect } from 'vitest';
+import type { Event, TransactionEvent } from '@sentry/types';
+
+export async function testResults(events: Event[]): Promise<void> {
+  // Get all transaction events (which represent traces)
+  const transactionEvents = events.filter((event): event is TransactionEvent => event.type === 'transaction');
+
+  // Should have at least 2 transaction events (one for each withMonitor call)
+  expect(transactionEvents.length).toBeGreaterThanOrEqual(2);
+
+  // Get trace IDs from the transactions
+  const traceIds = transactionEvents.map(event => event.contexts?.trace?.trace_id).filter(Boolean);
+
+  // Should have at least 2 different trace IDs (verifying trace isolation)
+  const uniqueTraceIds = [...new Set(traceIds)];
+  expect(uniqueTraceIds.length).toBeGreaterThanOrEqual(2);
+
+  console.log('✅ Found traces with different trace IDs:', uniqueTraceIds);
+}