hermes-agent/tests/hermes_cli/test_context_switch_guard.py

"""Tests for hermes_cli.context_switch_guard."""

from __future__ import annotations

from types import SimpleNamespace

from hermes_cli.context_switch_guard import merge_preflight_compression_warning
from hermes_cli.model_switch import ModelSwitchResult


def _result(*, model: str = "small-model") -> ModelSwitchResult:
    return ModelSwitchResult(
        success=True,
        new_model=model,
        target_provider="openrouter",
        provider_changed=False,
        api_key="k",
        base_url="https://example.com/v1",
        api_mode="chat_completions",
        provider_label="openrouter",
        model_info={"context_length": 32_000},
    )


def _compressor(monkeypatch, *, context_length: int = 200_000):
    from agent.context_compressor import ContextCompressor

    monkeypatch.setattr(
        "agent.context_compressor.get_model_context_length",
        lambda *a, **k: context_length,
    )
    return ContextCompressor(
        model="big-model",
        threshold_percent=0.5,
        protect_first_n=3,
        protect_last_n=20,
        quiet_mode=True,
        config_context_length=context_length,
    )


def test_no_warning_when_below_new_threshold(monkeypatch):
    monkeypatch.setattr(
        "hermes_cli.context_switch_guard.resolve_display_context_length",
        lambda *a, **k: 32_000,
    )
    cc = _compressor(monkeypatch)
    cc.last_prompt_tokens = 10_000
    agent = SimpleNamespace(
        context_compressor=cc,
        compression_enabled=True,
        conversation_history=[],
        base_url="",
        api_key="",
    )
    result = _result()
    merge_preflight_compression_warning(result, agent=agent)
    assert not result.warning_message


def test_warns_when_estimate_exceeds_new_threshold(monkeypatch):
    monkeypatch.setattr(
        "hermes_cli.context_switch_guard.resolve_display_context_length",
        lambda *a, **k: 32_000,
    )
    monkeypatch.setattr(
        "hermes_cli.context_switch_guard._estimate_tokens",
        lambda *a, **k: 90_000,
    )
    cc = _compressor(monkeypatch)
    agent = SimpleNamespace(
        context_compressor=cc,
        compression_enabled=True,
        conversation_history=[],
        base_url="",
        api_key="",
    )
    result = _result()
    merge_preflight_compression_warning(result, agent=agent)
    assert result.warning_message
    assert "preflight compression" in result.warning_message
    assert "shrinks" in result.warning_message


def test_merge_appends_to_existing_warning(monkeypatch):
    monkeypatch.setattr(
        "hermes_cli.context_switch_guard._estimate_tokens",
        lambda *a, **k: 90_000,
    )
    monkeypatch.setattr(
        "hermes_cli.context_switch_guard.resolve_display_context_length",
        lambda *a, **k: 32_000,
    )
    cc = _compressor(monkeypatch)
    agent = SimpleNamespace(
        context_compressor=cc,
        compression_enabled=True,
        base_url="",
        api_key="",
    )
    result = _result()
    result.warning_message = "expensive"
    merge_preflight_compression_warning(result, agent=agent)
    assert "expensive" in result.warning_message
    assert "preflight compression" in result.warning_message


def test_cross_route_switch_does_not_inherit_current_context_pin(monkeypatch):
    def _resolve_metadata(*_args, **kwargs):
        return kwargs["config_context_length"] or 32_000

    monkeypatch.setattr(
        "agent.model_metadata.get_model_context_length",
        _resolve_metadata,
    )
    monkeypatch.setattr(
        "hermes_cli.context_switch_guard._estimate_tokens",
        lambda *a, **k: 90_000,
    )
    cc = _compressor(monkeypatch, context_length=1_048_576)
    agent = SimpleNamespace(
        model="shared-model",
        provider="custom",
        context_compressor=cc,
        compression_enabled=True,
        conversation_history=[],
        base_url="https://large.example/v1",
        api_key="",
    )
    result = _result(model="shared-model")

    merge_preflight_compression_warning(
        result,
        agent=agent,
        config_context_length=1_048_576,
    )

    assert "preflight compression" in result.warning_message