Atomic Maestro Sessions + Shutdown gate

Co-Authored-By: brekotis <93345790+brekotis@users.noreply.github.com>

src/transport/upstream.rs

@@ -2052,6 +2052,45 @@ mod tests {
     const TEST_SHADOWSOCKS_URL: &str =
         "ss://2022-blake3-aes-256-gcm:MDEyMzQ1Njc4OTAxMjM0NTY3ODkwMTIzNDU2Nzg5MDE=@127.0.0.1:8388";
 
+    fn manager_with_dns(entries: &[String]) -> UpstreamManager {
+        UpstreamManager::new(Vec::new(), 1, 1, 1, 1, 1, false, Arc::new(Stats::new()))
+            .with_dns_overrides(entries)
+            .unwrap()
+    }
+
+    #[tokio::test]
+    async fn generation_local_dns_overrides_are_isolated_and_case_insensitive() {
+        let active = manager_with_dns(&["Front.Example:443:192.0.2.10".to_string()]);
+        let candidate = manager_with_dns(&["front.example:443:[2001:db8::10]".to_string()]);
+
+        assert_eq!(
+            active.resolve_hostname("front.example", 443).await.unwrap(),
+            "192.0.2.10:443".parse::<SocketAddr>().unwrap()
+        );
+        assert_eq!(
+            candidate
+                .resolve_hostname("FRONT.EXAMPLE", 443)
+                .await
+                .unwrap(),
+            "[2001:db8::10]:443".parse::<SocketAddr>().unwrap()
+        );
+
+        candidate
+            .update_dns_overrides(&["front.example:443:192.0.2.20".to_string()])
+            .unwrap();
+        assert_eq!(
+            active.resolve_hostname("FRONT.EXAMPLE", 443).await.unwrap(),
+            "192.0.2.10:443".parse::<SocketAddr>().unwrap()
+        );
+        assert_eq!(
+            candidate
+                .resolve_hostname("front.example", 443)
+                .await
+                .unwrap(),
+            "192.0.2.20:443".parse::<SocketAddr>().unwrap()
+        );
+    }
+
     #[test]
     fn required_healthy_group_count_applies_three_group_threshold() {
         assert_eq!(UpstreamManager::required_healthy_group_count(0), 0);