tests/unit/utils/test_config.py

"""Unit tests for configuration loading."""

import os
from unittest.mock import patch

import pytest
from pydantic import ValidationError

from src.utils.config import Settings
from src.utils.exceptions import ConfigurationError


class TestSettings:
    """Tests for Settings class.

    Note: We use _env_file=None to disable .env file reading in tests.
    This ensures tests are isolated from the developer's local .env file.
    pydantic-settings reads from both os.environ AND .env file by default.
    """

    def test_default_max_iterations(self) -> None:
        """Settings should have default max_iterations of 10."""
        with patch.dict(os.environ, {}, clear=True):
            settings = Settings(_env_file=None)
            assert settings.max_iterations == 10  # noqa: PLR2004

    def test_max_iterations_from_env(self) -> None:
        """Settings should read MAX_ITERATIONS from env."""
        with patch.dict(os.environ, {"MAX_ITERATIONS": "25"}, clear=True):
            settings = Settings(_env_file=None)
            assert settings.max_iterations == 25  # noqa: PLR2004

    def test_invalid_max_iterations_raises(self) -> None:
        """Settings should reject invalid max_iterations."""
        with patch.dict(os.environ, {"MAX_ITERATIONS": "100"}, clear=True):
            with pytest.raises(ValidationError):
                Settings(_env_file=None)  # 100 > 50 (max)

    def test_get_api_key_openai(self) -> None:
        """get_api_key should return OpenAI key when provider is openai."""
        with patch.dict(
            os.environ,
            {"LLM_PROVIDER": "openai", "OPENAI_API_KEY": "sk-test-key"},
            clear=True,
        ):
            settings = Settings(_env_file=None)
            assert settings.get_api_key() == "sk-test-key"

    def test_get_api_key_openai_missing_raises(self) -> None:
        """get_api_key should raise ConfigurationError when OpenAI key is not set."""
        with patch.dict(os.environ, {"LLM_PROVIDER": "openai"}, clear=True):
            settings = Settings(_env_file=None)
            with pytest.raises(ConfigurationError, match="OPENAI_API_KEY not set"):
                settings.get_api_key()