[router] migrate router from actix to axum (#8479)

sgl-router/tests/common/test_app.rs

@@ -0,0 +1,42 @@
+use axum::Router;
+use reqwest::Client;
+use sglang_router_rs::{
+    config::RouterConfig,
+    routers::RouterTrait,
+    server::{build_app, AppState},
+};
+use std::sync::Arc;
+
+/// Create a test Axum application using the actual server's build_app function
+pub fn create_test_app(
+    router: Arc<dyn RouterTrait>,
+    client: Client,
+    router_config: &RouterConfig,
+) -> Router {
+    // Create AppState with the test router
+    let app_state = Arc::new(AppState {
+        router,
+        client,
+        _concurrency_limiter: Arc::new(tokio::sync::Semaphore::new(
+            router_config.max_concurrent_requests,
+        )),
+    });
+
+    // Configure request ID headers (use defaults if not specified)
+    let request_id_headers = router_config.request_id_headers.clone().unwrap_or_else(|| {
+        vec![
+            "x-request-id".to_string(),
+            "x-correlation-id".to_string(),
+            "x-trace-id".to_string(),
+            "request-id".to_string(),
+        ]
+    });
+
+    // Use the actual server's build_app function
+    build_app(
+        app_state,
+        router_config.max_payload_size,
+        request_id_headers,
+        router_config.cors_allowed_origins.clone(),
+    )
+}