diff --git a/LOTUS_BUGS.md b/LOTUS_BUGS.md
index 6daf74e05..098f81293 100644
--- a/LOTUS_BUGS.md
+++ b/LOTUS_BUGS.md
@@ -151,7 +151,7 @@ retry … AbortError: Restart delayed event timed out before the HS responded`,
 
 ### Code Hygiene / DevEx
 
-- **Automated test suite — 231 tests across ~26 modules, a hard CI gate.** `npm test` runs Node's built-in runner via `tsx` (not vitest — Vite 8 is ahead of vitest's range) and **blocks the build job on failure**. Broad pure-logic coverage: utils (common, regex, sanitize/XSS, time, matrix, matrix-uia, mimeTypes, sort, accentColor, findAndReplace, AsyncSearch, ASCIILexicalTable, keyboard, room, matrix-crypto, featureCheck), state (settings, sessions, recentSearches, upload, typingMembers), plugins (matrix-to, call/utils, markdown/utils), lotus/avatarDecorations, search filters. Prevention work has caught + fixed **2 real bugs** (`findAndReplace` infinite-loop; `getSettings` crash-on-load when storage is blocked). **Next:** component/integration tests (the untestable-under-tsx DOM/React surface).
+- **Automated test suite — 527 tests across 60 modules, a hard CI gate.** `npm test` runs Node's built-in runner via `tsx` (not vitest — Vite 8 is ahead of vitest's range) and **blocks the build job on failure**. Broad pure-logic coverage: utils (common, regex, sanitize/XSS, time, matrix, matrix-uia, mimeTypes, sort, accentColor, findAndReplace, AsyncSearch, ASCIILexicalTable, keyboard, room, matrix-crypto, featureCheck, syntaxHighlight, imageCompression, user-agent, callSounds), state (settings, sessions, recentSearches, upload, typingMembers, lists, room-list, toast, scheduledMessages, backupRestore, callEmbed/callPreferences, spaceRooms, …), plugins (matrix-to, call/utils, via-servers, bad-words, recent-emoji, custom-emoji, markdown block/inline/utils), OIDC (cs-api, useParsedLoginFlows, oidcState), lotus/avatarDecorations, message-search, search filters. Prevention work has caught + fixed **3 real bugs** (`findAndReplace` infinite-loop; `getSettings` crash-on-load when storage is blocked; `isMacOS` never matching modern Macs). **Next:** component/integration tests (the untestable-under-tsx DOM/React surface).
 - **Extensive `as any` casts** across `src/` — gradual typing cleanup.
 - **`types/matrix/` mirrors SDK types** instead of importing them — drift risk.
 - **Hardcoded CDN URL** should move to an env var (the decoration CDN is now single-sourced in `avatarDecorations.ts`, but the literal is still in-repo).
diff --git a/src/app/utils/callSounds.test.ts b/src/app/utils/callSounds.test.ts
new file mode 100644
index 000000000..5ddb45dfc
--- /dev/null
+++ b/src/app/utils/callSounds.test.ts
@@ -0,0 +1,229 @@
+import { test, beforeEach } from 'node:test';
+import assert from 'node:assert/strict';
+
+import { playCallJoinSound, playCallLeaveSound, unlockCallSounds } from './callSounds';
+
+// ── Minimal Web Audio mock ──────────────────────────────────────────────────
+// callSounds.ts reaches for the global `AudioContext` lazily (inside its own
+// getAudioContext), so we can swap a fake in before each test and inspect the
+// oscillators/gains it schedules.
+
+type RampCall = { value: number; time: number };
+
+class FakeParam {
+  value = 0;
+  setValueAtTimeCalls: RampCall[] = [];
+  linearRampCalls: RampCall[] = [];
+  expRampCalls: RampCall[] = [];
+  setValueAtTime(value: number, time: number): this {
+    this.setValueAtTimeCalls.push({ value, time });
+    return this;
+  }
+  linearRampToValueAtTime(value: number, time: number): this {
+    this.linearRampCalls.push({ value, time });
+    return this;
+  }
+  exponentialRampToValueAtTime(value: number, time: number): this {
+    this.expRampCalls.push({ value, time });
+    return this;
+  }
+}
+
+class FakeOscillator {
+  type = 'sine';
+  frequency = { value: 0 };
+  startCalls: number[] = [];
+  stopCalls: number[] = [];
+  connectedTo: unknown = null;
+  connect(node: unknown): unknown {
+    this.connectedTo = node;
+    return node;
+  }
+  start(t: number): void {
+    this.startCalls.push(t);
+  }
+  stop(t: number): void {
+    this.stopCalls.push(t);
+  }
+}
+
+class FakeGain {
+  gain = new FakeParam();
+  connectedTo: unknown = null;
+  connect(node: unknown): unknown {
+    this.connectedTo = node;
+    return node;
+  }
+}
+
+class FakeAudioContext {
+  static instances: FakeAudioContext[] = [];
+  static throwOnConstruct = false;
+
+  state: 'running' | 'suspended' | 'closed' = 'running';
+  // currentTime 0 keeps `start = now + at` exactly equal to the table offsets
+  // (no float drift), so scheduling assertions stay precise.
+  currentTime = 0;
+  destination = { id: 'destination' };
+  oscillators: FakeOscillator[] = [];
+  gains: FakeGain[] = [];
+  resumeCalls = 0;
+
+  constructor() {
+    if (FakeAudioContext.throwOnConstruct) throw new Error('AudioContext unavailable');
+    FakeAudioContext.instances.push(this);
+  }
+  createOscillator(): FakeOscillator {
+    const osc = new FakeOscillator();
+    this.oscillators.push(osc);
+    return osc;
+  }
+  createGain(): FakeGain {
+    const gain = new FakeGain();
+    this.gains.push(gain);
+    return gain;
+  }
+  resume(): Promise<void> {
+    this.resumeCalls += 1;
+    this.state = 'running';
+    return Promise.resolve();
+  }
+  close(): Promise<void> {
+    this.state = 'closed';
+    return Promise.resolve();
+  }
+}
+
+const current = (): FakeAudioContext => {
+  const ctx = FakeAudioContext.instances.at(-1);
+  assert.ok(ctx, 'expected an AudioContext to have been created');
+  return ctx;
+};
+const freqs = (ctx: FakeAudioContext): number[] => ctx.oscillators.map((o) => o.frequency.value);
+
+beforeEach(() => {
+  // The module keeps a single shared AudioContext. Close any instance it may
+  // still hold so the next call forces a fresh one, then reset our registry.
+  FakeAudioContext.instances.forEach((i) => {
+    i.state = 'closed';
+  });
+  FakeAudioContext.instances = [];
+  FakeAudioContext.throwOnConstruct = false;
+  (globalThis as unknown as { AudioContext: unknown }).AudioContext = FakeAudioContext;
+});
+
+// ── Sound design (regression-pins the melodies) ─────────────────────────────
+
+test('chime join plays D5 then A5 as sine notes, staggered', () => {
+  playCallJoinSound('chime');
+  const ctx = current();
+  assert.equal(ctx.oscillators.length, 2);
+  assert.deepEqual(
+    ctx.oscillators.map((o) => o.type),
+    ['sine', 'sine'],
+  );
+  assert.deepEqual(freqs(ctx), [587.33, 880]);
+  assert.deepEqual(
+    ctx.oscillators.map((o) => o.startCalls[0]),
+    [0, 0.1],
+  );
+});
+
+test('chime leave reverses the join melody', () => {
+  playCallLeaveSound('chime');
+  assert.deepEqual(freqs(current()), [880, 587.33]);
+});
+
+test('soft join is a single triangle note at the right gain', () => {
+  playCallJoinSound('soft');
+  const ctx = current();
+  assert.equal(ctx.oscillators.length, 1);
+  assert.equal(ctx.oscillators[0].type, 'triangle');
+  assert.equal(ctx.oscillators[0].frequency.value, 523.25);
+  assert.equal(ctx.gains[0].gain.linearRampCalls[0].value, 0.18);
+});
+
+test('soft leave drops to the lower triangle note', () => {
+  playCallLeaveSound('soft');
+  assert.deepEqual(freqs(current()), [392]);
+});
+
+test('retro join is three ascending square notes', () => {
+  playCallJoinSound('retro');
+  const ctx = current();
+  assert.deepEqual(
+    ctx.oscillators.map((o) => o.type),
+    ['square', 'square', 'square'],
+  );
+  assert.deepEqual(freqs(ctx), [440, 554.37, 659.25]);
+  assert.deepEqual(
+    ctx.oscillators.map((o) => o.startCalls[0]),
+    [0, 0.07, 0.14],
+  );
+});
+
+test('retro leave is three descending square notes', () => {
+  playCallLeaveSound('retro');
+  assert.deepEqual(freqs(current()), [659.25, 554.37, 440]);
+});
+
+// ── Envelope (click-avoidance shape) ────────────────────────────────────────
+
+test('each note ramps 0 -> peak -> ~0 to avoid clicks, and wires osc->gain->out', () => {
+  playCallJoinSound('soft');
+  const ctx = current();
+  const { gain } = ctx.gains[0];
+  assert.equal(gain.setValueAtTimeCalls[0].value, 0); // starts silent
+  assert.equal(gain.linearRampCalls[0].value, 0.18); // attack to peak
+  assert.equal(gain.expRampCalls[0].value, 0.0001); // exp decay can't hit 0
+  // osc -> gain -> destination
+  assert.equal(ctx.oscillators[0].connectedTo, ctx.gains[0]);
+  assert.equal(ctx.gains[0].connectedTo, ctx.destination);
+  assert.equal(ctx.oscillators[0].startCalls.length, 1);
+  assert.equal(ctx.oscillators[0].stopCalls.length, 1);
+});
+
+// ── Dispatch / defensive contracts ──────────────────────────────────────────
+
+test('an unknown style is a no-op and never even creates a context', () => {
+  assert.doesNotThrow(() => playCallJoinSound('bogus' as never));
+  assert.doesNotThrow(() => playCallLeaveSound('bogus' as never));
+  assert.equal(FakeAudioContext.instances.length, 0);
+});
+
+test('does not throw when AudioContext construction fails (unsupported env)', () => {
+  FakeAudioContext.throwOnConstruct = true;
+  assert.doesNotThrow(() => playCallJoinSound('chime'));
+  assert.equal(FakeAudioContext.instances.length, 0);
+});
+
+// ── Shared-context lifecycle ────────────────────────────────────────────────
+
+test('unlockCallSounds primes a single running context', () => {
+  unlockCallSounds();
+  assert.equal(FakeAudioContext.instances.length, 1);
+  assert.equal(current().state, 'running');
+});
+
+test('reuses one running context across multiple sounds', () => {
+  playCallJoinSound('chime');
+  playCallLeaveSound('chime');
+  playCallJoinSound('soft');
+  assert.equal(FakeAudioContext.instances.length, 1);
+});
+
+test('recreates the context after it has been closed', () => {
+  playCallJoinSound('soft');
+  current().state = 'closed';
+  playCallJoinSound('soft');
+  assert.equal(FakeAudioContext.instances.length, 2);
+});
+
+test('resumes (without recreating) a suspended context', () => {
+  playCallJoinSound('soft');
+  const ctx = current();
+  ctx.state = 'suspended';
+  playCallJoinSound('soft');
+  assert.equal(FakeAudioContext.instances.length, 1);
+  assert.equal(ctx.resumeCalls, 1);
+});