Implement DashScope ASR provider and enhance ASR service architecture

- Added DashScope ASR service implementation for real-time streaming.
- Updated ASR provider logic to support DashScope alongside existing providers.
- Enhanced runtime metadata resolution to include DashScope as a valid ASR provider.
- Modified configuration files and documentation to reflect the addition of DashScope.
- Introduced tests to validate DashScope integration and ASR service behavior.
- Refactored ASR service factory to accommodate new provider options and modes.

engine/tests/test_duplex_asr_modes.py

@@ -0,0 +1,196 @@
+import asyncio
+from typing import Any, Dict, List
+
+import pytest
+
+from runtime.pipeline.duplex import DuplexPipeline
+
+
+class _DummySileroVAD:
+    def __init__(self, *args, **kwargs):
+        pass
+
+    def process_audio(self, _pcm: bytes) -> float:
+        return 0.0
+
+
+class _DummyVADProcessor:
+    def __init__(self, *args, **kwargs):
+        pass
+
+    def process(self, _speech_prob: float):
+        return "Silence", 0.0
+
+
+class _DummyEouDetector:
+    def __init__(self, *args, **kwargs):
+        self.is_speaking = True
+
+    def process(self, _vad_status: str, force_eligible: bool = False) -> bool:
+        _ = force_eligible
+        return False
+
+    def reset(self) -> None:
+        self.is_speaking = False
+
+
+class _FakeTransport:
+    async def send_event(self, _event: Dict[str, Any]) -> None:
+        return None
+
+    async def send_audio(self, _audio: bytes) -> None:
+        return None
+
+
+class _FakeStreamingASR:
+    mode = "streaming"
+
+    def __init__(self):
+        self.begin_calls = 0
+        self.end_calls = 0
+        self.wait_calls = 0
+        self.sent_audio: List[bytes] = []
+        self.wait_text = ""
+
+    async def connect(self) -> None:
+        return None
+
+    async def disconnect(self) -> None:
+        return None
+
+    async def send_audio(self, audio: bytes) -> None:
+        self.sent_audio.append(audio)
+
+    async def receive_transcripts(self):
+        if False:
+            yield None
+
+    async def begin_utterance(self) -> None:
+        self.begin_calls += 1
+
+    async def end_utterance(self) -> None:
+        self.end_calls += 1
+
+    async def wait_for_final_transcription(self, timeout_ms: int = 800) -> str:
+        _ = timeout_ms
+        self.wait_calls += 1
+        return self.wait_text
+
+    def clear_utterance(self) -> None:
+        return None
+
+
+class _FakeOfflineASR:
+    mode = "offline"
+
+    def __init__(self):
+        self.start_interim_calls = 0
+        self.stop_interim_calls = 0
+        self.sent_audio: List[bytes] = []
+        self.final_text = "offline final"
+
+    async def connect(self) -> None:
+        return None
+
+    async def disconnect(self) -> None:
+        return None
+
+    async def send_audio(self, audio: bytes) -> None:
+        self.sent_audio.append(audio)
+
+    async def receive_transcripts(self):
+        if False:
+            yield None
+
+    async def start_interim_transcription(self) -> None:
+        self.start_interim_calls += 1
+
+    async def stop_interim_transcription(self) -> None:
+        self.stop_interim_calls += 1
+
+    async def get_final_transcription(self) -> str:
+        return self.final_text
+
+    def clear_buffer(self) -> None:
+        return None
+
+    def get_and_clear_text(self) -> str:
+        return self.final_text
+
+
+def _build_pipeline(monkeypatch, asr_service):
+    monkeypatch.setattr("runtime.pipeline.duplex.SileroVAD", _DummySileroVAD)
+    monkeypatch.setattr("runtime.pipeline.duplex.VADProcessor", _DummyVADProcessor)
+    monkeypatch.setattr("runtime.pipeline.duplex.EouDetector", _DummyEouDetector)
+    return DuplexPipeline(
+        transport=_FakeTransport(),
+        session_id="asr_mode_test",
+        asr_service=asr_service,
+    )
+
+
+@pytest.mark.asyncio
+async def test_start_asr_capture_uses_streaming_begin(monkeypatch):
+    asr = _FakeStreamingASR()
+    pipeline = _build_pipeline(monkeypatch, asr)
+    pipeline._asr_mode = "streaming"
+    pipeline._pending_speech_audio = b"\x00" * 320
+    pipeline._pre_speech_buffer = b"\x00" * 640
+
+    await pipeline._start_asr_capture()
+
+    assert asr.begin_calls == 1
+    assert asr.sent_audio
+    assert pipeline._asr_capture_active is True
+
+
+@pytest.mark.asyncio
+async def test_start_asr_capture_uses_offline_interim_control(monkeypatch):
+    asr = _FakeOfflineASR()
+    pipeline = _build_pipeline(monkeypatch, asr)
+    pipeline._asr_mode = "offline"
+    pipeline._pending_speech_audio = b"\x00" * 320
+    pipeline._pre_speech_buffer = b"\x00" * 640
+
+    await pipeline._start_asr_capture()
+
+    assert asr.start_interim_calls == 1
+    assert asr.sent_audio
+    assert pipeline._asr_capture_active is True
+
+
+@pytest.mark.asyncio
+async def test_streaming_eou_falls_back_to_latest_interim(monkeypatch):
+    asr = _FakeStreamingASR()
+    asr.wait_text = ""
+    pipeline = _build_pipeline(monkeypatch, asr)
+    pipeline._asr_mode = "streaming"
+    pipeline._asr_capture_active = True
+    pipeline._latest_asr_interim_text = "fallback interim text"
+    await pipeline.conversation.start_user_turn()
+
+    captured_events = []
+    captured_turns = []
+
+    async def _capture_event(event: Dict[str, Any], priority: int = 20):
+        _ = priority
+        captured_events.append(event)
+
+    async def _noop_stop_current_speech() -> None:
+        return None
+
+    async def _capture_turn(user_text: str, *args, **kwargs) -> None:
+        _ = (args, kwargs)
+        captured_turns.append(user_text)
+
+    monkeypatch.setattr(pipeline, "_send_event", _capture_event)
+    monkeypatch.setattr(pipeline, "_stop_current_speech", _noop_stop_current_speech)
+    monkeypatch.setattr(pipeline, "_handle_turn", _capture_turn)
+
+    await pipeline._on_end_of_utterance()
+    await asyncio.sleep(0.05)
+
+    assert asr.end_calls == 1
+    assert asr.wait_calls == 1
+    assert captured_turns == ["fallback interim text"]
+    assert any(event.get("type") == "transcript.final" for event in captured_events)