Add more slot update notifications (#15734)

* Add more slot update notifications

* fix merge

* Address feedback and add integration test

* switch to datapoint

* remove unused shred method

* fix clippy

* new thread for rpc completed slots

* remove extra constant

* fixes

* rely on channel closing

* fix check

core/tests/rpc.rs

@@ -7,12 +7,13 @@ use serde_json::{json, Value};
 use solana_account_decoder::UiAccount;
 use solana_client::{
     rpc_client::RpcClient,
-    rpc_response::{Response, RpcSignatureResult},
+    rpc_response::{Response, RpcSignatureResult, SlotUpdate},
 };
 use solana_core::{rpc_pubsub::gen_client::Client as PubsubClient, test_validator::TestValidator};
 use solana_sdk::{
     commitment_config::CommitmentConfig,
     hash::Hash,
+    pubkey::Pubkey,
     signature::{Keypair, Signer},
     system_transaction,
     transaction::Transaction,
@@ -20,7 +21,7 @@ use solana_sdk::{
 use std::{
     collections::HashSet,
     net::UdpSocket,
-    sync::mpsc::channel,
+    sync::{mpsc::channel, Arc},
     thread::sleep,
     time::{Duration, Instant},
 };
@@ -140,6 +141,70 @@ fn test_rpc_invalid_requests() {
     assert!(the_value.is_null());
 }
 
+#[test]
+fn test_rpc_slot_updates() {
+    solana_logger::setup();
+
+    let test_validator = TestValidator::with_no_fees(Pubkey::new_unique());
+
+    // Create the pub sub runtime
+    let rt = Runtime::new().unwrap();
+    let rpc_pubsub_url = test_validator.rpc_pubsub_url();
+    let (update_sender, update_receiver) = channel::<Arc<SlotUpdate>>();
+
+    // Subscribe to slot updates
+    rt.spawn(async move {
+        let connect = ws::try_connect::<PubsubClient>(&rpc_pubsub_url).unwrap();
+        let client = connect.await.unwrap();
+
+        tokio_02::spawn(async move {
+            let mut update_sub = client.slots_updates_subscribe().unwrap();
+            loop {
+                let response = update_sub.next().await.unwrap();
+                update_sender.send(response.unwrap()).unwrap();
+            }
+        });
+    });
+
+    let first_update = update_receiver
+        .recv_timeout(Duration::from_secs(2))
+        .unwrap();
+
+    // Verify that updates are received in order for an upcoming slot
+    let verify_slot = first_update.slot() + 2;
+    let mut expected_update_index = 0;
+    let expected_updates = vec![
+        "CreatedBank",
+        "Completed",
+        "Frozen",
+        "OptimisticConfirmation",
+        "Root",
+    ];
+
+    let test_start = Instant::now();
+    loop {
+        assert!(test_start.elapsed() < Duration::from_secs(30));
+        let update = update_receiver
+            .recv_timeout(Duration::from_secs(2))
+            .unwrap();
+        if update.slot() == verify_slot {
+            let update_name = match *update {
+                SlotUpdate::CreatedBank { .. } => "CreatedBank",
+                SlotUpdate::Completed { .. } => "Completed",
+                SlotUpdate::Frozen { .. } => "Frozen",
+                SlotUpdate::OptimisticConfirmation { .. } => "OptimisticConfirmation",
+                SlotUpdate::Root { .. } => "Root",
+                _ => continue,
+            };
+            assert_eq!(update_name, expected_updates[expected_update_index]);
+            expected_update_index += 1;
+            if expected_update_index == expected_updates.len() {
+                break;
+            }
+        }
+    }
+}
+
 #[test]
 fn test_rpc_subscriptions() {
     solana_logger::setup();