applied copilot suggestions

Author: seriousme

test/helper.js

@@ -253,10 +253,18 @@ export async function withTimeout (promise, timeoutMs, timeoutResult) {
 }
 
 /**
- * @param {Object} parser - The emitter object
- * @param {Readable} sourceStream - The source stream to read MQTT packets from
- * @param {Object} opts - low and high water mark
- * @returns {AsyncGenerator} An async generator that yields MQTT packets
+ * Asynchronously yields MQTT packets parsed from a source stream, with backpressure management.
+ *
+ * Backpressure is controlled using a queue and the `highWaterMark`/`lowWaterMark` parameters:
+ * - When the number of buffered packets in the queue reaches `highWaterMark`, the source stream is paused to prevent overload.
+ * - When the queue size drops to or below `lowWaterMark`, the source stream is resumed to allow more data to flow.
+ *
+ * @param {Object} parser - The emitter object that parses MQTT packets and emits 'packet' events.
+ * @param {Readable} sourceStream - The source stream to read MQTT packets from.
+ * @param {Object} [opts] - Options for backpressure control.
+ * @param {number} [opts.highWaterMark=2] - Maximum number of packets to buffer before pausing the source stream.
+ * @param {number} [opts.lowWaterMark=0] - Minimum number of packets in the buffer to resume the source stream.
+ * @returns {AsyncGenerator<Object|null, void, unknown>} An async generator that yields MQTT packets, or null when done.
  */
 async function * packetGenerator (parser, sourceStream, opts = {
   highWaterMark: 2,

test/will.js

@@ -55,7 +55,7 @@ test('delivers a will', async (t) => {
 
   const { packet } = await oneWillFromBroker(s.broker)
   t.assert.equal(packet.topic, opts.will.topic, 'topic matches')
-  t.assert.deepEqual(structuredClone(packet).payload, opts.will.payload, 'payload matches')
+  t.assert.deepEqual(packet.payload, opts.will.payload, 'payload matches')
   t.assert.equal(packet.qos, opts.will.qos, 'qos matches')
   t.assert.equal(packet.retain, opts.will.retain, 'retain matches')
 })
@@ -109,7 +109,7 @@ test('delivers old will in case of a crash', async (t) => {
   const { packet, received } = await oneWillFromBroker(broker)
   t.assert.ok(Date.now() - start >= 3 * interval, 'the will needs to be emitted after 3 heartbeats')
   t.assert.equal(packet.topic, will.topic, 'topic matches')
-  t.assert.deepEqual(structuredClone(packet).payload, will.payload, 'payload matches')
+  t.assert.deepEqual(packet.payload, will.payload, 'payload matches')
   t.assert.equal(packet.qos, will.qos, 'qos matches')
   t.assert.equal(packet.retain, will.retain, 'retain matches')
   t.assert.equal(authorized, true, 'authorization called')