fix blank screen on load

tests/http_security.rs

@@ -85,6 +85,32 @@ fn request(peer: &str) -> Request<axum::body::Body> {
     request
 }
 
+#[tokio::test]
+async fn frontend_security_policy_allows_its_external_assets() {
+    let (app, _dir, _tx) = app().await;
+    let mut request = Request::builder()
+        .uri("/")
+        .body(axum::body::Body::empty())
+        .unwrap();
+    request.extensions_mut().insert(ConnectInfo(
+        "203.0.113.4:5000".parse::<SocketAddr>().unwrap(),
+    ));
+
+    let response = app.oneshot(request).await.unwrap();
+
+    assert_eq!(response.status(), StatusCode::OK);
+    assert_eq!(
+        response.headers()[header::CONTENT_SECURITY_POLICY],
+        "default-src 'self'; connect-src 'self' ws: wss:; style-src 'self'; script-src 'self'; frame-ancestors 'none'"
+    );
+    let body = axum::body::to_bytes(response.into_body(), 8192)
+        .await
+        .unwrap();
+    let html = String::from_utf8(body.to_vec()).unwrap();
+    assert!(html.contains("rel=\"stylesheet\""));
+    assert!(!html.contains("<style"));
+}
+
 #[tokio::test]
 async fn authorized_direct_ip_receives_redacted_logs() {
     let (app, _dir, _tx) = app().await;