test: integration test to tuono_lib (#425)

crates/tuono_lib/tests/utils/health_check.rs

@@ -0,0 +1,7 @@
+use tuono_lib::axum::http::StatusCode;
+use tuono_lib::Request;
+
+#[tuono_lib::api(GET)]
+async fn health_check(_req: Request) -> StatusCode {
+    StatusCode::OK
+}