feat: add Pydantic Settings configuration

pyproject.toml

@@ -23,3 +23,12 @@ dev = [
 [project.scripts]
 start = "uvicorn src.backend.main:app --host 0.0.0.0 --port 8000"
 dev = "uvicorn src.backend.main:app --reload --host 0.0.0.0 --port 8000"
+
+[dependency-groups]
+dev = [
+    "pytest>=9.0.3",
+    "pytest-asyncio>=1.3.0",
+]
+
+[tool.pytest.ini_options]
+asyncio_mode = "auto"

src/backend/config.py

@@ -0,0 +1,25 @@
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    api_host: str = "0.0.0.0"
+    api_port: int = 8000
+
+    api_key: str
+
+    rate_limit_per_minute: int = 10
+    rate_limit_per_hour: int = 100
+
+    worker_url: str = "http://claude-worker:3001"
+
+    db_path: str = "/data/opus-agent.db"
+
+    claude_model: str = "claude-sonnet-4-6"
+
+    model_config = {
+        "env_file": ".env",
+        "env_file_encoding": "utf-8",
+    }
+
+
+settings = Settings()

tests/conftest.py

@@ -0,0 +1,30 @@
+import os
+import tempfile
+
+_test_dir = tempfile.mkdtemp()
+
+os.environ.setdefault("API_KEY", "test-key-12345")
+os.environ.setdefault("DB_PATH", os.path.join(_test_dir, "test.db"))
+os.environ.setdefault("WORKER_URL", "http://localhost:3001")
+os.environ.setdefault("CLAUDE_MODEL", "claude-sonnet-4-6")
+os.environ.setdefault("RATE_LIMIT_PER_MINUTE", "100")
+os.environ.setdefault("RATE_LIMIT_PER_HOUR", "1000")
+os.environ.setdefault("API_HOST", "0.0.0.0")
+os.environ.setdefault("API_PORT", "8000")
+
+import pytest
+
+
+@pytest.fixture(autouse=True)
+async def setup_db():
+    from src.backend.db.database import init_db, get_db
+
+    await init_db()
+    yield
+    db = await get_db()
+    try:
+        await db.execute("DELETE FROM requests")
+        await db.execute("DELETE FROM topics")
+        await db.commit()
+    finally:
+        await db.close()

tests/test_services.py

@@ -0,0 +1,111 @@
+from src.backend.config import settings
+
+import pytest
+
+
+def test_settings_loads_api_key():
+    assert settings.api_key == "test-key-12345"
+
+
+def test_settings_loads_db_path():
+    assert "test.db" in settings.db_path
+
+
+def test_settings_loads_worker_url():
+    assert settings.worker_url == "http://localhost:3001"
+
+
+def test_settings_loads_claude_model():
+    assert settings.claude_model == "claude-sonnet-4-6"
+
+
+def test_settings_loads_rate_limits():
+    assert settings.rate_limit_per_minute == 100
+    assert settings.rate_limit_per_hour == 1000
+
+
+@pytest.mark.asyncio
+async def test_init_db_creates_tables():
+    from src.backend.db.database import init_db, get_db
+
+    await init_db()
+    db = await get_db()
+    try:
+        cursor = await db.execute(
+            "SELECT name FROM sqlite_master WHERE type='table' ORDER BY name"
+        )
+        tables = [row[0] for row in await cursor.fetchall()]
+        assert "topics" in tables
+        assert "requests" in tables
+    finally:
+        await db.close()
+
+
+@pytest.mark.asyncio
+async def test_foreign_keys_enabled():
+    from src.backend.db.database import init_db, get_db
+
+    await init_db()
+    db = await get_db()
+    try:
+        cursor = await db.execute("PRAGMA foreign_keys")
+        row = await cursor.fetchone()
+        assert row[0] == 1
+    finally:
+        await db.close()
+
+
+def test_topic_create_model_validates():
+    from src.backend.models.api import TopicCreate
+
+    topic = TopicCreate(
+        name="coding",
+        system_prompt="You are an expert coder.",
+        summary="Coding questions",
+        model="claude-sonnet-4-6",
+    )
+    assert topic.name == "coding"
+    assert topic.model == "claude-sonnet-4-6"
+
+
+def test_topic_create_model_optional_fields():
+    from src.backend.models.api import TopicCreate
+
+    topic = TopicCreate(name="coding", system_prompt="You are an expert coder.")
+    assert topic.summary == ""
+    assert topic.model is None
+
+
+def test_request_create_model_validates():
+    from src.backend.models.api import RequestCreate
+
+    req = RequestCreate(
+        prompt="How to do X?",
+        topic_id="550e8400-e29b-41d4-a716-446655440000",
+    )
+    assert req.session_id is None
+    assert req.model is None
+    assert req.summarize is False
+
+
+def test_model_validation_rejects_invalid():
+    from src.backend.models.api import TopicCreate
+    from pydantic import ValidationError
+
+    with pytest.raises(ValidationError):
+        TopicCreate(name="test", system_prompt="test", model="gpt-4")
+
+
+def test_envelope_ok():
+    from src.backend.models.api import ok
+
+    result = ok({"key": "value"})
+    assert result == {"success": True, "data": {"key": "value"}, "error": None}
+
+
+def test_envelope_fail():
+    from src.backend.models.api import fail
+
+    result = fail("NOT_FOUND", "Resource not found")
+    assert result["success"] is False
+    assert result["error"]["code"] == "NOT_FOUND"