add required bearer auth token

tests/test_auth.py

@@ -0,0 +1,29 @@
+from fastapi.testclient import TestClient
+from tailscalesd.main import Settings, app, get_settings
+
+client = TestClient(app)
+
+
+def get_settings_override() -> Settings:
+    return Settings(test_mode=True, tailnet="test", api_key="test", bearer_token="test")
+
+
+app.dependency_overrides[get_settings] = get_settings_override
+
+
+def test_auth_works():
+    response = client.get("/", headers={"Authorization": "Bearer test"})
+    assert response.status_code == 200
+    assert response.json() == []
+
+
+def test_unauthorized_wrong_token():
+    response = client.get("/", headers={"Authorization": "Bearer incorrect_token"})
+    assert response.status_code == 401
+    assert response.json() == {"detail": "Invalid authentication credentials"}
+
+
+def test_unauthorized_no_token():
+    response = client.get("/")
+    assert response.status_code == 403
+    assert response.json() == {"detail": "Not authenticated"}