hermes-agent/tests/tools/test_browser_vision_model.py

"""Tests for browser_tool._get_vision_model() — Gemma 4 default (Issue #816).

Covers acceptance criteria from issue #816:
- Browser screenshots use Gemma 4 by default.
- BROWSER_VISION_MODEL env var overrides the model for browser vision only.
- AUXILIARY_VISION_MODEL env var still works as a global override.
- auxiliary.browser_vision.model in config.yaml overrides the default.
- Priority: BROWSER_VISION_MODEL > config.yaml > AUXILIARY_VISION_MODEL > default.
"""

import importlib
import sys
from unittest.mock import patch, MagicMock

import pytest


def _reload_and_get(monkeypatch, env: dict, cfg: dict | None = None):
    """Reload browser_tool with patched env vars and optional config, return _get_vision_model."""
    # Patch environment
    for k, v in env.items():
        monkeypatch.setenv(k, v)

    # Patch load_config if a config dict is provided
    if cfg is not None:
        mock_load = MagicMock(return_value=cfg)
        monkeypatch.setattr("hermes_cli.config.load_config", mock_load, raising=False)

    # We import the function directly rather than reloading the heavy module
    # to keep tests fast.  Import browser_tool once and call the function with
    # patched globals each time.
    import tools.browser_tool as bt
    return bt._get_vision_model


class TestGetVisionModelDefault:
    def test_default_is_gemma4(self, monkeypatch):
        monkeypatch.delenv("BROWSER_VISION_MODEL", raising=False)
        monkeypatch.delenv("AUXILIARY_VISION_MODEL", raising=False)
        import tools.browser_tool as bt
        model = bt._get_vision_model()
        assert model == "google/gemma-4-27b-it"

    def test_default_constant(self):
        import tools.browser_tool as bt
        assert bt._BROWSER_VISION_DEFAULT_MODEL == "google/gemma-4-27b-it"


class TestGetVisionModelEnvOverrides:
    def test_browser_vision_model_env_takes_priority(self, monkeypatch):
        monkeypatch.setenv("BROWSER_VISION_MODEL", "openai/gpt-4o")
        monkeypatch.setenv("AUXILIARY_VISION_MODEL", "google/gemini-3-flash-preview")
        import tools.browser_tool as bt
        assert bt._get_vision_model() == "openai/gpt-4o"

    def test_auxiliary_vision_model_fallback(self, monkeypatch):
        monkeypatch.delenv("BROWSER_VISION_MODEL", raising=False)
        monkeypatch.setenv("AUXILIARY_VISION_MODEL", "google/gemini-3-flash-preview")
        import tools.browser_tool as bt
        assert bt._get_vision_model() == "google/gemini-3-flash-preview"

    def test_browser_vision_model_empty_falls_through(self, monkeypatch):
        """Empty BROWSER_VISION_MODEL should fall through to next step."""
        monkeypatch.setenv("BROWSER_VISION_MODEL", "")
        monkeypatch.delenv("AUXILIARY_VISION_MODEL", raising=False)
        import tools.browser_tool as bt
        # Should reach the default
        assert bt._get_vision_model() == "google/gemma-4-27b-it"

    def test_auxiliary_vision_model_empty_falls_through(self, monkeypatch):
        monkeypatch.delenv("BROWSER_VISION_MODEL", raising=False)
        monkeypatch.setenv("AUXILIARY_VISION_MODEL", "")
        import tools.browser_tool as bt
        assert bt._get_vision_model() == "google/gemma-4-27b-it"


class TestGetVisionModelConfig:
    def test_config_overrides_default(self, monkeypatch):
        monkeypatch.delenv("BROWSER_VISION_MODEL", raising=False)
        monkeypatch.delenv("AUXILIARY_VISION_MODEL", raising=False)
        cfg = {"auxiliary": {"browser_vision": {"model": "anthropic/claude-3-5-haiku"}}}
        with patch("hermes_cli.config.load_config", return_value=cfg):
            import tools.browser_tool as bt
            assert bt._get_vision_model() == "anthropic/claude-3-5-haiku"

    def test_config_empty_string_falls_through_to_default(self, monkeypatch):
        monkeypatch.delenv("BROWSER_VISION_MODEL", raising=False)
        monkeypatch.delenv("AUXILIARY_VISION_MODEL", raising=False)
        cfg = {"auxiliary": {"browser_vision": {"model": ""}}}
        with patch("hermes_cli.config.load_config", return_value=cfg):
            import tools.browser_tool as bt
            assert bt._get_vision_model() == "google/gemma-4-27b-it"

    def test_config_load_error_falls_through_to_default(self, monkeypatch):
        monkeypatch.delenv("BROWSER_VISION_MODEL", raising=False)
        monkeypatch.delenv("AUXILIARY_VISION_MODEL", raising=False)
        with patch("hermes_cli.config.load_config", side_effect=Exception("config error")):
            import tools.browser_tool as bt
            assert bt._get_vision_model() == "google/gemma-4-27b-it"

    def test_env_beats_config(self, monkeypatch):
        monkeypatch.setenv("BROWSER_VISION_MODEL", "openai/gpt-4o")
        cfg = {"auxiliary": {"browser_vision": {"model": "anthropic/claude-3-5-haiku"}}}
        with patch("hermes_cli.config.load_config", return_value=cfg):
            import tools.browser_tool as bt
            assert bt._get_vision_model() == "openai/gpt-4o"

    def test_config_beats_auxiliary_vision_model(self, monkeypatch):
        """Config should override AUXILIARY_VISION_MODEL when BROWSER_VISION_MODEL unset."""
        monkeypatch.delenv("BROWSER_VISION_MODEL", raising=False)
        monkeypatch.setenv("AUXILIARY_VISION_MODEL", "global-override")
        cfg = {"auxiliary": {"browser_vision": {"model": "config-model"}}}
        with patch("hermes_cli.config.load_config", return_value=cfg):
            import tools.browser_tool as bt
            assert bt._get_vision_model() == "config-model"


class TestBackwardCompatibility:
    """AUXILIARY_VISION_MODEL must still work for users who already have it configured."""

    def test_existing_auxiliary_vision_model_not_broken(self, monkeypatch):
        """Users who set AUXILIARY_VISION_MODEL must not be broken by this change."""
        monkeypatch.delenv("BROWSER_VISION_MODEL", raising=False)
        monkeypatch.setenv("AUXILIARY_VISION_MODEL", "openai/gpt-4o")
        import tools.browser_tool as bt
        with patch("hermes_cli.config.load_config", return_value={}):
            model = bt._get_vision_model()
        assert model == "openai/gpt-4o"
        assert model != "google/gemma-4-27b-it"