test(core): Add integration test for getTracingHeadersForFetchRequest

This adds an integration test that demonstrates cross-package usage of the
getTracingHeadersForFetchRequest function exported from @sentry/core.
The test validates that the function correctly generates tracing headers
(sentry-trace and baggage) when called from another package within an
active span context.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: cursoragent

dev-packages/node-integration-tests/suites/public-api/getTracingHeadersForFetchRequest/basic-usage/scenario.ts

@@ -0,0 +1,30 @@
+import*asSentryfrom'@sentry/node';
+import{getTracingHeadersForFetchRequest}from'@sentry/core';
+import{loggingTransport}from'@sentry-internal/node-integration-tests';
+
+Sentry.init({
+dsn: 'https://public@dsn.ingest.sentry.io/1337',
+tracesSampleRate: 1.0,
+transport: loggingTransport,
+});
+
+Sentry.startSpan({name: 'test-span'},()=>{
+constheaders=getTracingHeadersForFetchRequest('https://example.com/api',{});
+
+if(!headers||typeofheaders!=='object'||Array.isArray(headers)){
+thrownewError('getTracingHeadersForFetchRequest returned invalid headers');
+}
+
+constsentryTrace='sentry-trace'inheaders ? headers['sentry-trace'] : undefined;
+constbaggage='baggage'inheaders ? headers.baggage : undefined;
+
+if(!sentryTrace||typeofsentryTrace!=='string'||!sentryTrace.match(/^[0-9a-f]{32}-[0-9a-f]{16}-[01]$/)){
+thrownewError('sentry-trace header is invalid or missing');
+}
+
+if(!baggage||typeofbaggage!=='string'||!baggage.includes('sentry-')){
+thrownewError('baggage header is invalid or missing');
+}
+
+Sentry.captureMessage('test message');
+});

dev-packages/node-integration-tests/suites/public-api/getTracingHeadersForFetchRequest/basic-usage/test.ts

@@ -0,0 +1,17 @@
+import{afterAll,test}from'vitest';
+import{cleanupChildProcesses,createRunner}from'../../../../utils/runner';
+
+afterAll(()=>{
+cleanupChildProcesses();
+});
+
+test('should generate tracing headers for fetch request',async()=>{
+awaitcreateRunner(__dirname,'scenario.ts')
+.expect({
+event: {
+message: 'test message',
+},
+})
+.start()
+.completed();
+});