test: Fix withMonitor integration test to use proper test runner

Rewrite integration test to use createRunner pattern like other tests.
Test now properly captures check-ins and verifies distinct trace IDs
when isolateTrace is enabled, following PR review feedback.

Author: naaa760

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

@@ -1,28 +1,40 @@
-import { withMonitor } from '@sentry/node';
+import * as Sentry from '@sentry/node';
+import { loggingTransport } from '@sentry-internal/node-integration-tests';
 
-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: '* * * * *' }
+Sentry.init({
+  dsn: 'https://[email protected]/1337',
+  release: '1.0',
+  transport: loggingTransport,
+});
+
+// First withMonitor call without isolateTrace
+// eslint-disable-next-line @sentry-internal/sdk/no-floating-promises
+Sentry.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
+// Second withMonitor call with isolateTrace (should have different trace)
+// eslint-disable-next-line @sentry-internal/sdk/no-floating-promises
+Sentry.withMonitor('cron-job-2', async () => {
+  // Simulate some work
+  await new Promise<void>((resolve) => {
+    setTimeout(() => {
+      resolve();
+    }, 100);
   });
-}
+}, {
+  schedule: { type: 'crontab', value: '* * * * *' },
+  isolateTrace: true,
+});
+
+// Wait a bit for check-ins to complete before exiting
+setTimeout(() => {
+  process.exit();
+}, 500);

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

@@ -1,19 +1,51 @@
-import { expect } from 'vitest';
-import type { Event, TransactionEvent } from '@sentry/types';
+import type { SerializedCheckIn } from '@sentry/core';
+import { afterAll, describe, expect, test } from 'vitest';
+import { cleanupChildProcesses, createRunner } from '../../../utils/runner';
 
-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');
+describe('withMonitor isolateTrace', () => {
+  afterAll(() => {
+    cleanupChildProcesses();
+  });
 
-  // Should have at least 2 transaction events (one for each withMonitor call)
-  expect(transactionEvents.length).toBeGreaterThanOrEqual(2);
+  test('creates distinct traces when isolateTrace is enabled', async () => {
+    const checkIns: SerializedCheckIn[] = [];
 
-  // Get trace IDs from the transactions
-  const traceIds = transactionEvents.map(event => event.contexts?.trace?.trace_id).filter(Boolean);
+    await createRunner(__dirname, 'scenario.ts')
+      .expect({
+        check_in: checkIn => {
+          checkIns.push(checkIn);
+        },
+      })
+      .expect({
+        check_in: checkIn => {
+          checkIns.push(checkIn);
+        },
+      })
+      .expect({
+        check_in: checkIn => {
+          checkIns.push(checkIn);
+        },
+      })
+      .expect({
+        check_in: checkIn => {
+          checkIns.push(checkIn);
+        },
+      })
+      .start()
+      .completed();
 
-  // Should have at least 2 different trace IDs (verifying trace isolation)
-  const uniqueTraceIds = [...new Set(traceIds)];
-  expect(uniqueTraceIds.length).toBeGreaterThanOrEqual(2);
+    // Find the two 'ok' check-ins for comparison
+    const checkIn1Ok = checkIns.find(c => c.monitor_slug === 'cron-job-1' && c.status === 'ok');
+    const checkIn2Ok = checkIns.find(c => c.monitor_slug === 'cron-job-2' && c.status === 'ok');
 
-  console.log('✅ Found traces with different trace IDs:', uniqueTraceIds);
-}
+    expect(checkIn1Ok).toBeDefined();
+    expect(checkIn2Ok).toBeDefined();
+
+    // Verify both check-ins have trace contexts
+    expect(checkIn1Ok!.contexts?.trace?.trace_id).toBeDefined();
+    expect(checkIn2Ok!.contexts?.trace?.trace_id).toBeDefined();
+
+    // The key assertion: trace IDs should be different when isolateTrace is enabled
+    expect(checkIn1Ok!.contexts!.trace!.trace_id).not.toBe(checkIn2Ok!.contexts!.trace!.trace_id);
+  });
+});