Fix timing issue in pg_groups integration test

Signed-off-by: Kan-Ru Chen <[email protected]>

ractor_cluster_integration_tests/src/tests/pg_groups.rs

@@ -176,6 +176,22 @@ pub(crate) async fn test(config: PgGroupsConfig) -> i32 {
         rpc_reply = ractor::call_t!(actor, ractor_cluster::NodeServerMessage::GetSessions, 200);
     }
 
+    // wait until at least one remote actor has spawned
+    let tic = Instant::now();
+    loop {
+        let duration = Instant::now() - tic;
+        if duration.as_millis() > HELLO_ALLOTED_MS {
+            tracing::error!("Remote actor didn't join in allotted time");
+            return -1;
+        }
+        if ractor::pg::get_members(&"test".into())
+            .iter()
+            .any(|actor| !actor.get_id().is_local())
+        {
+            break;
+        }
+    }
+
     if err_code == 0 {
         // we're authenticated. Startup our PG group testing
         let _ = ractor::cast!(test_actor, HelloActorMessage::Hey("Hey there".to_string()));