core/lmproto: coerce developer role for chat completions

tests/test_lmproto/test_chat_compat.py

@@ -0,0 +1,90 @@
+"""Compatibility normalization for chat-completions wire requests."""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+import msgspec
+
+from plyngent.lmproto.deepseek.openai_compat.model import ChatCompletionsParam as DeepseekChatCompletionsParam
+from plyngent.lmproto.openai_compatible.compat import (
+    coerce_chat_completions_param,
+    coerce_chat_completions_param_any,
+    coerce_developer_messages_to_system,
+    developer_to_system_message,
+)
+from plyngent.lmproto.openai_compatible.model import (
+    AnyChatMessage,
+    AssistantChatMessage,
+    ChatCompletionsParam,
+    DeveloperChatMessage,
+    SystemChatMessage,
+    UserChatMessage,
+)
+
+
+def _roles(messages: Sequence[object]) -> list[str]:
+    raw = msgspec.json.decode(msgspec.json.encode(messages))
+    return [str(item["role"]) for item in raw]
+
+
+def test_developer_to_system_message_preserves_content_and_name() -> None:
+    msg = DeveloperChatMessage(content="follow these rules", name="policy")
+    converted = developer_to_system_message(msg)
+    assert isinstance(converted, SystemChatMessage)
+    assert converted.content == "follow these rules"
+    assert converted.name == "policy"
+
+
+def test_coerce_developer_messages_to_system() -> None:
+    messages: list[AnyChatMessage] = [
+        SystemChatMessage(content="system"),
+        DeveloperChatMessage(content="dev"),
+        UserChatMessage(content="hi"),
+        AssistantChatMessage(content="hello"),
+    ]
+    coerced = coerce_developer_messages_to_system(messages)
+    assert coerced is not messages
+    assert _roles(coerced) == ["system", "system", "user", "assistant"]
+    assert coerced[1].content == "dev"
+
+
+def test_coerce_returns_equal_list_when_no_developer() -> None:
+    messages: list[AnyChatMessage] = [SystemChatMessage(content="system"), UserChatMessage(content="hi")]
+    assert coerce_developer_messages_to_system(messages) == messages
+
+
+def test_coerce_chat_param_encodes_without_developer_role() -> None:
+    param = ChatCompletionsParam(
+        model="model",
+        messages=[
+            DeveloperChatMessage(content="dev"),
+            UserChatMessage(content="hi"),
+        ],
+    )
+    coerced = coerce_chat_completions_param(param)
+    raw = msgspec.json.decode(msgspec.json.encode(coerced))
+    assert raw["messages"][0]["role"] == "system"
+    assert raw["messages"][1]["role"] == "user"
+
+
+def test_deepseek_param_accepts_coerced_messages() -> None:
+    base = ChatCompletionsParam(
+        model="deepseek",
+        messages=[DeveloperChatMessage(content="dev"), UserChatMessage(content="hi")],
+    )
+    coerced = coerce_chat_completions_param(base)
+    raw = msgspec.json.decode(msgspec.json.encode(coerced))
+    deepseek_param = msgspec.convert(raw, DeepseekChatCompletionsParam)
+    assert _roles(deepseek_param.messages) == ["system", "user"]
+
+
+def test_generic_coercion_handles_deepseek_runtime_param() -> None:
+    base = ChatCompletionsParam(
+        model="deepseek",
+        messages=[DeveloperChatMessage(content="dev"), UserChatMessage(content="hi")],
+    )
+    # Runtime calls may pass a generic param through a DeepSeek-typed method.
+    coerced = coerce_chat_completions_param_any(base)
+    raw = msgspec.json.decode(msgspec.json.encode(coerced))
+    assert raw["messages"][0]["role"] == "system"