test: add unit tests for config loader (strix/config/loader.py) (#596)

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_config_loader.py

@@ -0,0 +1,178 @@
+"""Tests for strix.config.loader: JSON overrides, alias resolution, persistence."""
+
+from __future__ import annotations
+
+import json
+from typing import TYPE_CHECKING
+
+import pytest
+from pydantic import AliasChoices, Field
+from pydantic.fields import FieldInfo
+
+from strix.config import loader
+
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+
+_LLM_ENV_KEYS = [
+    "STRIX_LLM",
+    "LLM_API_KEY",
+    "OPENAI_API_KEY",
+    "LLM_API_BASE",
+    "OPENAI_API_BASE",
+    "OPENAI_BASE_URL",
+    "LITELLM_BASE_URL",
+    "OLLAMA_API_BASE",
+    "STRIX_REASONING_EFFORT",
+    "LLM_TIMEOUT",
+    "PERPLEXITY_API_KEY",
+    # RuntimeSettings
+    "STRIX_IMAGE",
+    "STRIX_RUNTIME_BACKEND",
+    "STRIX_MAX_LOCAL_COPY_MB",
+    # TelemetrySettings
+    "STRIX_TELEMETRY",
+]
+
+
+@pytest.fixture(autouse=True)
+def _reset_loader_state(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Reset module globals and clear known env vars for deterministic runs."""
+    for key in _LLM_ENV_KEYS:
+        monkeypatch.delenv(key, raising=False)
+    monkeypatch.setattr(loader, "_cached", None)
+    monkeypatch.setattr(loader, "_override", None)
+
+
+# --------------------------------------------------------------------------- #
+# _read_json_overrides
+# --------------------------------------------------------------------------- #
+
+
+def test_read_json_overrides_missing_file(tmp_path: Path) -> None:
+    assert loader._read_json_overrides(tmp_path / "nope.json") == {}
+
+
+def test_read_json_overrides_corrupt_json(tmp_path: Path) -> None:
+    path = tmp_path / "cli-config.json"
+    path.write_text("{not valid json", encoding="utf-8")
+    assert loader._read_json_overrides(path) == {}
+
+
+def test_read_json_overrides_non_dict_env(tmp_path: Path) -> None:
+    path = tmp_path / "cli-config.json"
+    path.write_text(json.dumps({"env": ["not", "a", "dict"]}), encoding="utf-8")
+    assert loader._read_json_overrides(path) == {}
+
+
+def test_read_json_overrides_maps_to_nested_settings(tmp_path: Path) -> None:
+    path = tmp_path / "cli-config.json"
+    path.write_text(
+        json.dumps({"env": {"STRIX_LLM": "my-model", "PERPLEXITY_API_KEY": "pk"}}),
+        encoding="utf-8",
+    )
+    assert loader._read_json_overrides(path) == {
+        "llm": {"model": "my-model"},
+        "integrations": {"perplexity_api_key": "pk"},
+    }
+
+
+def test_read_json_overrides_skips_keys_already_in_environ(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    monkeypatch.setenv("STRIX_LLM", "from-env")
+    path = tmp_path / "cli-config.json"
+    path.write_text(json.dumps({"env": {"STRIX_LLM": "from-file"}}), encoding="utf-8")
+    # env wins -> the JSON value is not surfaced as an init kwarg.
+    assert loader._read_json_overrides(path) == {}
+
+
+# --------------------------------------------------------------------------- #
+# _aliases_for
+# --------------------------------------------------------------------------- #
+
+
+def test_aliases_for_simple_alias() -> None:
+    finfo = FieldInfo(alias="SIMPLE_ALIAS")
+    assert loader._aliases_for(finfo) == ["SIMPLE_ALIAS"]
+
+
+def test_aliases_for_alias_choices() -> None:
+    finfo: FieldInfo = Field(  # type: ignore[assignment]
+        default=None,
+        validation_alias=AliasChoices("FIRST", "SECOND"),
+    )
+    assert loader._aliases_for(finfo) == ["FIRST", "SECOND"]
+
+
+def test_aliases_for_string_validation_alias() -> None:
+    finfo: FieldInfo = Field(default=None, validation_alias="STR_ALIAS")  # type: ignore[assignment]
+    assert loader._aliases_for(finfo) == ["STR_ALIAS"]
+
+
+def test_aliases_for_no_alias() -> None:
+    assert loader._aliases_for(FieldInfo()) == []
+
+
+# --------------------------------------------------------------------------- #
+# apply_config_override + load_settings round-trip
+# --------------------------------------------------------------------------- #
+
+
+def test_apply_override_and_load_settings_round_trip(tmp_path: Path) -> None:
+    path = tmp_path / "cli-config.json"
+    path.write_text(
+        json.dumps({"env": {"STRIX_LLM": "round-trip-model", "PERPLEXITY_API_KEY": "pk"}}),
+        encoding="utf-8",
+    )
+
+    loader.apply_config_override(path)
+    settings = loader.load_settings()
+
+    assert settings.llm.model == "round-trip-model"
+    assert settings.integrations.perplexity_api_key == "pk"
+    # Second call is memoized -> same object.
+    assert loader.load_settings() is settings
+
+
+def test_apply_config_override_invalidates_cache(tmp_path: Path) -> None:
+    first = tmp_path / "first.json"
+    first.write_text(json.dumps({"env": {"STRIX_LLM": "first-model"}}), encoding="utf-8")
+    second = tmp_path / "second.json"
+    second.write_text(json.dumps({"env": {"STRIX_LLM": "second-model"}}), encoding="utf-8")
+
+    loader.apply_config_override(first)
+    assert loader.load_settings().llm.model == "first-model"
+
+    loader.apply_config_override(second)
+    assert loader.load_settings().llm.model == "second-model"
+
+
+# --------------------------------------------------------------------------- #
+# persist_current
+# --------------------------------------------------------------------------- #
+
+
+def test_persist_current_writes_env_block(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("STRIX_LLM", "persisted-model")
+    target = tmp_path / "sub" / "cli-config.json"
+    loader.apply_config_override(target)
+
+    loader.persist_current()
+
+    assert target.exists()
+    assert json.loads(target.read_text(encoding="utf-8")) == {
+        "env": {"STRIX_LLM": "persisted-model"}
+    }
+
+
+def test_persist_current_sets_0600_mode(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("STRIX_LLM", "persisted-model")
+    target = tmp_path / "cli-config.json"
+    loader.apply_config_override(target)
+
+    loader.persist_current()
+
+    assert target.stat().st_mode & 0o777 == 0o600