fix: return tts:tokens-result when tts:tokens command is missing id (#1548) (#1577)

_lccTtsTokens silently returned on a missing `id`, leaving the WS client with
no feedback — no tts:tokens-result, no audio, only a server-side info log.
Mirror the existing missing-`tokens` handling and reply with status 'failed' /
reason 'missing id' so callers that omit `id` (e.g. the Python SDK) get an
actionable result.

test/index.js

@@ -4,6 +4,7 @@ require('./ws-requestor-unit-test');
 require('./http-requestor-retry-test');
 require('./http-requestor-unit-test');
 require('./unit-tests');
+require('./tts-tokens-missing-id-test');
 require('./hold-unhold-test');
 require('./docker_start');
 require('./create-test-db');

test/tts-tokens-missing-id-test.js

@@ -0,0 +1,34 @@
+const test = require('tape');
+const sinon = require('sinon');
+const CallSession = require('../lib/session/call-session');
+
+// Regression test for #1548: _lccTtsTokens must not silently drop a tts:tokens
+// command that is missing `id`. It should reply with a tts:tokens-result of
+// status 'failed'/reason 'missing id', mirroring how a missing `tokens` field
+// is already handled — otherwise the WS client (e.g. the Python SDK, which does
+// not send `id`) gets no feedback at all.
+
+const buildFakeSession = () => {
+  const requestor = { request: sinon.stub().resolves({}) };
+  const logger = { info: sinon.stub(), debug: sinon.stub() };
+  return { requestor, logger, ttsStreamingBuffer: { bufferTokens: sinon.stub().resolves({}) } };
+};
+
+test('_lccTtsTokens: missing id returns a failed tts:tokens-result instead of silently dropping', async (t) => {
+  const session = buildFakeSession();
+
+  // WHEN a tts:tokens command arrives without `id`
+  await CallSession.prototype._lccTtsTokens.call(session, {tokens: 'hello world'});
+
+  // THEN a tts:tokens-result with status 'failed'/reason 'missing id' is sent back
+  t.ok(session.requestor.request.calledOnce, 'requestor.request should be called once');
+  const [type, path, payload] = session.requestor.request.firstCall.args;
+  t.equal(type, 'tts:tokens-result', 'response type is tts:tokens-result');
+  t.equal(path, '/tokens-result', 'response path is /tokens-result');
+  t.equal(payload.status, 'failed', 'status is failed');
+  t.equal(payload.reason, 'missing id', 'reason is missing id');
+
+  // AND tokens are never buffered for an invalid command
+  t.ok(session.ttsStreamingBuffer.bufferTokens.notCalled, 'tokens are not buffered when id is missing');
+  t.end();
+});