rolling recording buffer

test/audio-clip-library.test.ts

@@ -0,0 +1,75 @@
+import assert from 'node:assert/strict'
+import { readFile } from 'node:fs/promises'
+import { mkdtemp, rm } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import test from 'node:test'
+import {
+  AudioClipLibrary,
+  buildAudioClipBaseName,
+  encodePcm16Wav,
+  validateAudioClipDragPayload,
+} from '../src/main/audioClipLibrary'
+import type { AudioClipDragPayload } from '../src/types/audioClip'
+
+function clipPayload(overrides: Partial<AudioClipDragPayload> = {}): AudioClipDragPayload {
+  return {
+    pcmBytes: new Uint8Array([0x00, 0x80, 0xff, 0x7f, 0x00, 0x00, 0x01, 0x00]),
+    sampleRate: 48000,
+    channelCount: 2,
+    frameCount: 2,
+    ...overrides,
+  }
+}
+
+test('validates rolling clip metadata and exact PCM byte count', () => {
+  assert.deepEqual(validateAudioClipDragPayload(clipPayload()), clipPayload())
+  assert.throws(() => validateAudioClipDragPayload(null), /payload is invalid/i)
+  assert.throws(() => validateAudioClipDragPayload(clipPayload({ sampleRate: 384001 })), /sample rate/i)
+  assert.throws(() => validateAudioClipDragPayload({
+    ...clipPayload(),
+    channelCount: 3,
+  }), /channel count/i)
+  assert.throws(() => validateAudioClipDragPayload(clipPayload({
+    frameCount: 48000 * 60 + 1,
+  })), /duration/i)
+  assert.throws(() => validateAudioClipDragPayload(clipPayload({
+    pcmBytes: new Uint8Array(6),
+  })), /data length/i)
+})
+
+test('encodes a standard little-endian 16-bit PCM WAV', () => {
+  const payload = clipPayload()
+  const wav = encodePcm16Wav(payload)
+
+  assert.equal(wav.toString('ascii', 0, 4), 'RIFF')
+  assert.equal(wav.readUInt32LE(4), 36 + payload.pcmBytes.byteLength)
+  assert.equal(wav.toString('ascii', 8, 12), 'WAVE')
+  assert.equal(wav.toString('ascii', 12, 16), 'fmt ')
+  assert.equal(wav.readUInt16LE(20), 1)
+  assert.equal(wav.readUInt16LE(22), 2)
+  assert.equal(wav.readUInt32LE(24), 48000)
+  assert.equal(wav.readUInt32LE(28), 192000)
+  assert.equal(wav.readUInt16LE(32), 4)
+  assert.equal(wav.readUInt16LE(34), 16)
+  assert.equal(wav.toString('ascii', 36, 40), 'data')
+  assert.equal(wav.readUInt32LE(40), payload.pcmBytes.byteLength)
+  assert.deepEqual(Array.from(wav.subarray(44)), Array.from(payload.pcmBytes))
+})
+
+test('writes persistent clips with safe timestamped collision-resistant names', async (t) => {
+  const parent = await mkdtemp(join(tmpdir(), 'prism-audio-clips-'))
+  t.after(async () => rm(parent, { recursive: true, force: true }))
+  const directory = join(parent, 'Prism Captures')
+  const now = new Date('2026-08-16T17:42:03.123Z')
+  const library = new AudioClipLibrary(directory, () => now)
+
+  assert.equal(buildAudioClipBaseName(now), 'Prism Clip 2026-08-16 17-42-03.123')
+  const firstPath = library.writeClip(clipPayload())
+  const secondPath = library.writeClip(clipPayload())
+
+  assert.equal(firstPath, join(directory, 'Prism Clip 2026-08-16 17-42-03.123.wav'))
+  assert.equal(secondPath, join(directory, 'Prism Clip 2026-08-16 17-42-03.123 (2).wav'))
+  assert.deepEqual(await readFile(firstPath), encodePcm16Wav(clipPayload()))
+  assert.deepEqual(await readFile(secondPath), encodePcm16Wav(clipPayload()))
+})