validator/test: check VS cluster restart does not break setup

Add test restarting VS cluster and checking if the restart
does not break ScyllaDB connection to VS nodes.

Author: QuerthDP

crates/validator-vector-store/src/reconnect.rs

@@ -30,6 +30,11 @@ pub(crate) async fn new() -> TestCase {
             timeout,
             restarting_all_nodes_doesnt_break_fullscan,
         )
+        .with_test(
+            "restarting_vs_cluster_does_not_break_setup",
+            timeout,
+            test_restarting_vs_cluster_does_not_break_setup,
+        )
 }
 
 async fn reconnect_doesnt_break_fullscan(actors: TestActors) {
@@ -270,3 +275,58 @@ async fn restarting_all_nodes_doesnt_break_fullscan(actors: TestActors) {
 
     info!("finished");
 }
+
+async fn test_restarting_vs_cluster_does_not_break_setup(actors: TestActors) {
+    info!("started");
+
+    let (session, clients) = prepare_connection(&actors).await;
+
+    let keyspace = create_keyspace(&session).await;
+    let table = create_table(
+        &session,
+        "id INT PRIMARY KEY, embedding VECTOR<FLOAT, 3>",
+        None,
+    )
+    .await;
+
+    let stmt = session
+        .prepare(format!(
+            "INSERT INTO {table} (id, embedding) VALUES (?, [1.0, 2.0, 3.0])"
+        ))
+        .await
+        .expect("failed to prepare a statement");
+
+    for id in 0..1000 {
+        session
+            .execute_unpaged(&stmt, (id,))
+            .await
+            .expect("failed to insert a row");
+    }
+
+    let index = create_index(&session, &clients, &table, "embedding").await;
+
+    actors.vs.down().await;
+    actors.vs.up(get_default_vs_node_configs(&actors)).await;
+
+    for client in &clients {
+        let index_status = wait_for_index(client, &index).await;
+        assert_eq!(
+            index_status.count, 1000,
+            "Expected 1000 vectors to be indexed"
+        );
+    }
+
+    session
+        .query_unpaged(
+            format!("SELECT * FROM {table} ORDER BY embedding ANN OF [1.0, 2.0, 3.0] LIMIT 5"),
+            (),
+        )
+        .await
+        .expect("failed to query ANN search");
+
+    session
+        .query_unpaged(format!("DROP KEYSPACE {keyspace}"), ())
+        .await
+        .expect("failed to drop a keyspace");
+    info!("finished");
+}