tests(iroh-net): Make some tests less flaky (#2457)

## Description

This removes the flaky marker from a test that I haven't seen being
flaky in a while.

It also tries to put some waiting time in another test to make it less
flaky.

## Breaking Changes

<!-- Optional, if there are any breaking changes document them,
including how to migrate older code. -->

## Notes & open questions

<!-- Any notes, remarks or open questions you have to make about the PR.
-->

## Change checklist

- [x] Self-review.
- ~~[ ] Documentation updates if relevant.~~
- [x] Tests if relevant.
- ~~[ ] All breaking changes documented.~~

Co-authored-by: Rüdiger Klaehn <[email protected]>

iroh-net/src/endpoint.rs

@@ -1237,13 +1237,12 @@ mod tests {
 
     /// Test that peers saved on shutdown are correctly loaded
     #[tokio::test]
-    #[cfg_attr(target_os = "windows", ignore = "flaky")]
     async fn save_load_peers() {
         let _guard = iroh_test::logging::setup();
 
         let secret_key = SecretKey::generate();
         let root = testdir::testdir!();
-        let path = root.join("peers");
+        let peers_path = root.join("peers");
 
         /// Create an endpoint for the test.
         async fn new_endpoint(secret_key: SecretKey, peers_path: PathBuf) -> Endpoint {
@@ -1269,17 +1268,37 @@ mod tests {
         info!("setting up first endpoint");
         // first time, create a magic endpoint without peers but a peers file and add addressing
         // information for a peer
-        let endpoint = new_endpoint(secret_key.clone(), path.clone()).await;
+        let endpoint = new_endpoint(secret_key.clone(), peers_path.clone()).await;
         assert!(endpoint.connection_infos().is_empty());
         endpoint.add_node_addr(node_addr).unwrap();
 
         info!("closing endpoint");
         // close the endpoint and restart it
         endpoint.close(0u32.into(), b"done").await.unwrap();
 
+        // Give the destructors some time to create the file.  We use sync code to read the
+        // file here, it's just a test.
+        let now = Instant::now();
+        let mut previous_size = None;
+        while now.elapsed() < Duration::from_secs(10) {
+            if peers_path.is_file() {
+                let size = peers_path.metadata().unwrap().len();
+                match previous_size {
+                    None => previous_size = Some(size),
+                    Some(previous_size) => {
+                        if previous_size == size {
+                            // File is fully written
+                            break;
+                        }
+                    }
+                }
+            }
+            tokio::time::sleep(Duration::from_millis(100)).await;
+        }
+
         info!("restarting endpoint");
         // now restart it and check the addressing info of the peer
-        let endpoint = new_endpoint(secret_key, path).await;
+        let endpoint = new_endpoint(secret_key, peers_path).await;
         let ConnectionInfo { mut addrs, .. } = endpoint.connection_info(peer_id).unwrap();
         let conn_addr = addrs.pop().unwrap().addr;
         assert_eq!(conn_addr, direct_addr);

iroh-net/src/magicsock.rs

@@ -3027,7 +3027,6 @@ mod tests {
     }
 
     #[tokio::test(flavor = "multi_thread")]
-    #[ignore = "flaky"]
     async fn test_two_devices_roundtrip_network_change() -> Result<()> {
         time::timeout(
             Duration::from_secs(50),