test: add test to dynamic enablement of trace-events

PR-URL: https://github.com/nodejs/node/pull/22114
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-trace-events-dynamic-enable.js

@@ -0,0 +1,58 @@
+'use strict';
+
+const common = require('../common');
+
+common.skipIfInspectorDisabled();
+
+const assert = require('assert');
+const { performance } = require('perf_hooks');
+const { Session } = require('inspector');
+
+const session = new Session();
+
+function post(message, data) {
+  return new Promise((resolve, reject) => {
+    session.post(message, data, (err, result) => {
+      if (err)
+        reject(new Error(JSON.stringify(err)));
+      else
+        resolve(result);
+    });
+  });
+}
+
+async function test() {
+  session.connect();
+
+  let traceNotification = null;
+  let tracingComplete = false;
+  session.on('NodeTracing.dataCollected', (n) => traceNotification = n);
+  session.on('NodeTracing.tracingComplete', () => tracingComplete = true);
+
+  // Generate a node.perf event before tracing is enabled.
+  performance.mark('mark1');
+
+  const traceConfig = { includedCategories: ['node.perf'] };
+  await post('NodeTracing.start', { traceConfig });
+
+  // Generate a node.perf event after tracing is enabled. This should be the
+  // mark event captured.
+  performance.mark('mark2');
+
+  await post('NodeTracing.stop', { traceConfig });
+
+  performance.mark('mark3');
+
+  session.disconnect();
+
+  assert.ok(tracingComplete);
+  assert.ok(traceNotification);
+  assert.ok(traceNotification.data && traceNotification.data.value);
+
+  const events = traceNotification.data.value;
+  const marks = events.filter((t) => null !== /node\.perf\.usertim/.exec(t.cat));
+  assert.strictEqual(marks.length, 1);
+  assert.strictEqual(marks[0].name, 'mark2');
+}
+
+test();