devplacepy/tests/unit/services/devii/agentic/compaction.py

# retoor <retoor@molodetz.nl>

import json

from devplacepy.services.devii.agentic.compaction import (
    compact_messages,
    find_compaction_split,
    is_context_length_error,
)
from devplacepy.services.devii.errors import LLMError
from tests.conftest import run_async


def _error(status, body):
    return LLMError("Model endpoint returned error", status=status, body=body)


def test_openrouter_style_message_detected():
    body = json.dumps(
        {
            "error": {
                "message": (
                    "This endpoint's maximum context length is 131072 tokens. "
                    "However, you requested about 403355 tokens (349784 of text "
                    "input, 53571 of tool input). Please reduce the length of "
                    "either one, or use the context-compression plugin."
                ),
                "code": 400,
                "metadata": {"provider_name": None},
            }
        }
    )
    assert is_context_length_error(_error(400, body)) is True


def test_openai_style_code_detected():
    body = json.dumps(
        {
            "error": {
                "message": "This model's maximum context length is 128000 tokens.",
                "type": "invalid_request_error",
                "param": None,
                "code": "context_length_exceeded",
            }
        }
    )
    assert is_context_length_error(_error(400, body)) is True


def test_unrelated_400_not_detected():
    body = json.dumps({"error": {"message": "Invalid API key.", "code": 400}})
    assert is_context_length_error(_error(400, body)) is False


def test_non_400_status_not_detected_even_with_matching_text():
    body = json.dumps(
        {"error": {"message": "maximum context length is 131072 tokens"}}
    )
    assert is_context_length_error(_error(429, body)) is False


def test_malformed_body_falls_back_to_phrase_match():
    truncated = "maximum context length is 131072 tokens, please reduce the length"
    assert is_context_length_error(_error(400, truncated)) is True


def test_malformed_body_with_no_match_is_false():
    assert is_context_length_error(_error(400, "not valid json at all")) is False


class _StubLlm:
    def __init__(self, summary="a concise summary of the earlier turns"):
        self.summary = summary
        self.calls = 0

    async def summarize(self, prompt):
        self.calls += 1
        return self.summary


def _tool_call_message(name="run_tool"):
    return {
        "role": "assistant",
        "content": "",
        "tool_calls": [
            {"id": "c1", "function": {"name": name, "arguments": "{}"}}
        ],
    }


def _tool_result_message(content="result"):
    return {"role": "tool", "tool_call_id": "c1", "name": "run_tool", "content": content}


def _long_tool_heavy_conversation(rounds=20):
    messages = [
        {"role": "system", "content": "sys"},
        {"role": "user", "content": "start the long task"},
    ]
    for i in range(rounds):
        messages.append(_tool_call_message())
        messages.append(_tool_result_message(f"result {i}" * 200))
    return messages


def test_find_compaction_split_prefers_a_user_message():
    messages = [
        {"role": "system", "content": "sys"},
        {"role": "user", "content": "first"},
        {"role": "assistant", "content": "reply"},
        {"role": "user", "content": "second"},
        {"role": "assistant", "content": "reply2"},
        {"role": "user", "content": "third"},
        {"role": "assistant", "content": "reply3"},
    ]
    split = find_compaction_split(messages, keep_tail=2)
    assert messages[split]["role"] == "user"


def test_find_compaction_split_falls_back_to_a_non_tool_boundary_without_a_recent_user_message():
    messages = _long_tool_heavy_conversation(rounds=20)
    split = find_compaction_split(messages, keep_tail=4)
    assert split > 1
    assert messages[split].get("role") != "tool"


def test_find_compaction_split_never_lands_inside_a_tool_result_run():
    messages = _long_tool_heavy_conversation(rounds=30)
    for keep_tail in (2, 3, 4, 5, 8, 10, 15):
        split = find_compaction_split(messages, keep_tail)
        assert messages[split].get("role") != "tool", (
            f"keep_tail={keep_tail} split at a tool message, orphaning its tool_calls"
        )


def test_compact_messages_shrinks_a_tool_heavy_conversation_with_no_recent_user_message():
    messages = _long_tool_heavy_conversation(rounds=20)
    original_len = len(messages)
    llm = _StubLlm()
    compacted = run_async(compact_messages(llm, messages, keep_tail=4))
    assert llm.calls == 1
    assert len(compacted) < original_len
    assert compacted[0]["role"] == "system"
    assert "[compacted earlier turns]" in compacted[1]["content"]
    assert compacted[-1] == messages[-1]


def test_compact_messages_tail_never_starts_with_a_dangling_tool_result():
    messages = _long_tool_heavy_conversation(rounds=25)
    llm = _StubLlm()
    compacted = run_async(compact_messages(llm, messages, keep_tail=6))
    tail = compacted[2:]
    assert tail
    assert tail[0].get("role") != "tool"