test: improve test coverage of internal/worker/io

PR-URL: #41511
Refs: https://coverage.nodejs.org/coverage-74b9baa4265a8f0d/lib/internal/worker/io.js.html#L415
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

Author: kuriyosh

test/parallel/test-broadcastchannel-custom-inspect.js

@@ -0,0 +1,40 @@
+'use strict';
+
+require('../common');
+const{ BroadcastChannel }=require('worker_threads');
+const{ inspect }=require('util');
+constassert=require('assert');
+
+// This test checks BroadcastChannel custom inspect outputs
+
+{
+constbc=newBroadcastChannel('name');
+assert.throws(()=>bc[inspect.custom].call(),{
+code: 'ERR_INVALID_THIS',
+});
+bc.close();
+}
+
+{
+constbc=newBroadcastChannel('name');
+assert.strictEqual(inspect(bc,{depth: -1}),'BroadcastChannel');
+bc.close();
+}
+
+{
+constbc=newBroadcastChannel('name');
+assert.strictEqual(
+inspect(bc),
+"BroadcastChannel { name: 'name', active: true }"
+);
+bc.close();
+}
+
+{
+constbc=newBroadcastChannel('name');
+assert.strictEqual(
+inspect(bc,{depth: null}),
+"BroadcastChannel { name: 'name', active: true }"
+);
+bc.close();
+}