[Core] Give the OpenAI Realtime wire codec a reusable home (RFC #6592 P0a) (#7640)

Signed-off-by: psv666 <2693925048@qq.com>

tests/protocol/realtime/test_realtime_capabilities.py

@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
+
+"""``RealtimeProtocolCapabilities``: one consumer's answers, the codec's checking.
+
+This is the seam that lets a non-duplex Realtime surface validate a
+``session.update`` without a ``DuplexModelPlugin``. What it has to get right is
+narrow: the order the checks run in (formats before turn detection, because
+that is the order clients already see), the error codes, and that a consumer
+which declares a narrower format set is actually narrowed.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Mapping
+
+import pytest
+
+from vllm_omni.protocol.realtime.capabilities import (
+    RealtimeProtocolCapabilities,
+    RealtimeSessionRejection,
+    validate_session_payload,
+)
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
+_DEFAULT = RealtimeProtocolCapabilities()
+
+
+def test_a_consumer_without_a_turn_detection_check_accepts_a_plain_session():
+    assert (
+        validate_session_payload({"model": "m", "audio": {"input": {"format": "pcm16"}}}, capabilities=_DEFAULT) is None
+    )
+
+
+def test_a_consumer_without_a_turn_detection_check_ignores_turn_detection():
+    payload = {"turn_detection": {"type": "semantic_vad"}}
+
+    assert validate_session_payload(payload, capabilities=_DEFAULT) is None
+
+
+def test_an_unsupported_input_format_is_rejected_with_the_realtime_code():
+    rejection = validate_session_payload({"input_audio_format": "opus"}, capabilities=_DEFAULT)
+
+    assert rejection == RealtimeSessionRejection(
+        code="unsupported_audio_format", message="Unsupported input_audio_format: opus"
+    )
+
+
+def test_a_consumer_may_declare_a_narrower_format_set():
+    pcm_only = RealtimeProtocolCapabilities(input_audio_formats=frozenset({"pcm16"}))
+
+    assert validate_session_payload({"input_audio_format": "pcm16"}, capabilities=pcm_only) is None
+    rejection = validate_session_payload({"input_audio_format": "g711_ulaw"}, capabilities=pcm_only)
+    assert rejection is not None
+    assert rejection.code == "unsupported_audio_format"
+    # The default capabilities still accept it: the narrowing is per consumer.
+    assert validate_session_payload({"input_audio_format": "g711_ulaw"}, capabilities=_DEFAULT) is None
+
+
+def test_the_turn_detection_check_runs_and_reports_its_own_code():
+    def reject_everything(session_payload: Mapping[str, object]) -> str | None:
+        del session_payload
+        return "server_vad is not available"
+
+    capabilities = RealtimeProtocolCapabilities(validate_turn_detection=reject_everything)
+
+    rejection = validate_session_payload({"turn_detection": {"type": "server_vad"}}, capabilities=capabilities)
+
+    assert rejection == RealtimeSessionRejection(
+        code="unsupported_turn_detection", message="server_vad is not available", param="turn_detection"
+    )
+
+
+def test_a_bad_format_is_reported_before_a_bad_turn_detection():
+    calls: list[Mapping[str, object]] = []
+
+    def record(session_payload: Mapping[str, object]) -> str | None:
+        calls.append(session_payload)
+        return "turn detection is wrong too"
+
+    capabilities = RealtimeProtocolCapabilities(validate_turn_detection=record)
+
+    rejection = validate_session_payload(
+        {"input_audio_format": "opus", "turn_detection": {"type": "semantic_vad"}},
+        capabilities=capabilities,
+    )
+
+    assert rejection is not None
+    assert rejection.code == "unsupported_audio_format"
+    assert calls == []