feat: add configuration module with env-based settings

tests/test_config.py

@@ -0,0 +1,37 @@
+# tests/test_config.py
+import pytest
+
+from fastapi_oidc_op.config import Settings, StorageBackend
+
+
+def test_default_settings() -> None:
+    settings = Settings(
+        issuer="http://localhost:8000",
+    )
+    assert settings.issuer == "http://localhost:8000"
+    assert settings.storage_backend == StorageBackend.SQLITE
+    assert settings.sqlite_path == "data/oidc_op.db"
+    assert settings.manage_client_id == "manage-app"
+    assert settings.invite_ttl == 86400
+    assert settings.theme == "default"
+
+
+def test_mongodb_settings() -> None:
+    settings = Settings(
+        issuer="http://localhost:8000",
+        storage_backend=StorageBackend.MONGODB,
+        mongodb_uri="mongodb://mongo:27017",
+        mongodb_database="test_db",
+    )
+    assert settings.storage_backend == StorageBackend.MONGODB
+    assert settings.mongodb_uri == "mongodb://mongo:27017"
+    assert settings.mongodb_database == "test_db"
+
+
+def test_settings_from_env(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("OIDC_OP_ISSUER", "https://op.example.org")
+    monkeypatch.setenv("OIDC_OP_STORAGE_BACKEND", "mongodb")
+    monkeypatch.setenv("OIDC_OP_MONGODB_URI", "mongodb://remote:27017")
+    settings = Settings()  # type: ignore[call-arg]
+    assert settings.issuer == "https://op.example.org"
+    assert settings.storage_backend == StorageBackend.MONGODB