feat: add typed configuration loader with env support

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_config.py

@@ -0,0 +1,43 @@
+"""Tests for the application configuration loader."""
+
+import os
+from unittest.mock import patch
+
+from app.config import Settings, get_settings
+
+
+class TestSettings:
+    """Tests for the Settings configuration class."""
+
+    def test_settings_loads_defaults(self) -> None:
+        """Settings should have sensible defaults for all fields."""
+        with patch.dict(os.environ, {
+            "ADMIN_USERNAME": "testadmin",
+            "ADMIN_PASSWORD": "testpass123",
+        }, clear=False):
+            settings = Settings()
+            assert settings.admin_username == "testadmin"
+            assert settings.admin_password == "testpass123"
+            assert settings.app_env == "development"
+            assert settings.app_host == "0.0.0.0"
+            assert settings.app_port == 8000
+            assert settings.database_url == "sqlite:///data/sneakyswole.db"
+
+    def test_settings_requires_admin_username(self) -> None:
+        """Settings should require ADMIN_USERNAME to be set."""
+        with patch.dict(os.environ, {"ADMIN_PASSWORD": "testpass"}, clear=True):
+            try:
+                Settings()
+                assert False, "Should have raised an error"
+            except Exception:
+                pass
+
+    def test_get_settings_returns_singleton(self) -> None:
+        """get_settings should return the same instance on repeated calls."""
+        with patch.dict(os.environ, {
+            "ADMIN_USERNAME": "admin",
+            "ADMIN_PASSWORD": "pass",
+        }, clear=False):
+            s1 = get_settings()
+            s2 = get_settings()
+            assert s1 is s2