better output from this test for failure (failing with node 18 in CI,…

… but not locally for me)

metapackages/auto-instrumentations-node/test/register.test.ts

@@ -13,32 +13,38 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { promisify } from 'util';
-import * as childProcess from 'child_process';
-import * as assert from 'assert';
 
-const exec = promisify(childProcess.exec);
+import { spawnSync } from 'child_process';
+import * as assert from 'assert';
 
 describe('Register', function () {
   this.timeout(5000);
   it('can load auto instrumentation from command line', async () => {
-    process.env.OTEL_NODE_RESOURCE_DETECTORS = 'none';
-    process.env.OTEL_TRACES_EXPORTER = 'console';
-
-    const { stdout } = await exec(
-      'node --require ./build/src/register.js ./test/test-app/app.js'
+    const proc = spawnSync(
+      process.execPath,
+      ['--require', '../build/src/register.js', './test-app/app.js'],
+      {
+        cwd: __dirname,
+        timeout: 5000,
+        env: Object.assign(
+          {},
+          process.env,
+          {
+            OTEL_NODE_RESOURCE_DETECTORS: 'none',
+            OTEL_TRACES_EXPORTER: 'console',
+          }
+        )
+      }
     );
-
+    console.log('XXX proc: status=%s stdout=--\n%s\n-- stderr=--\n%s\n--', proc.status, proc.stdout, proc.stderr);
+    assert.ifError(proc.error);
     assert.ok(
-      stdout.includes(
+      proc.stdout.includes(
         'OpenTelemetry automatic instrumentation started successfully'
       )
     );
 
-    //Check a span has been generated for the GET request done in app.js
-    assert.ok(stdout.includes("name: 'GET'"));
-
-    delete process.env.OTEL_NODE_RESOURCE_DETECTORS;
-    delete process.env.OTEL_TRACES_EXPORTER;
+    // Check a span has been generated for the GET request done in app.js
+    assert.ok(proc.stdout.includes("name: 'GET'"));
   });
 });