fix(client): handle sequence wrap in reply ordering

crates/irtt-client/src/client/tests/sequence.rs

@@ -0,0 +1,45 @@
+use super::*;
+use std::time::Instant;
+
+use crate::{
+    probe::{CompletedSet, PendingMap, TimedOutMap},
+    session::ActiveSession,
+};
+
+#[test]
+fn sequence_ordering_handles_normal_and_wrapped_values() {
+    assert!(sequence_is_after(11, 10));
+    assert!(sequence_is_before(9, 10));
+    assert!(!sequence_is_after(10, 10));
+    assert!(!sequence_is_before(10, 10));
+
+    assert!(sequence_is_after(0, u32::MAX - 1));
+    assert!(!sequence_is_before(0, u32::MAX - 1));
+    assert!(sequence_is_after(1, u32::MAX));
+    assert!(!sequence_is_before(1, u32::MAX));
+
+    assert!(sequence_is_before(u32::MAX, 1));
+    assert!(!sequence_is_after(u32::MAX, 1));
+}
+
+#[test]
+fn highest_received_seq_updates_across_wrap() {
+    let mut session = ActiveSession {
+        next_wire_seq: 0,
+        next_logical_seq: 0,
+        highest_received_seq: Some(u32::MAX),
+        packets_sent: 0,
+        start_mono: Instant::now(),
+        end_mono: None,
+        next_send_at: Instant::now(),
+        pending: PendingMap::new(8),
+        timed_out: TimedOutMap::new(8),
+        completed: CompletedSet::new(8),
+        sending_done: false,
+    };
+
+    update_highest_received(&mut session, 0);
+    assert_eq!(session.highest_received_seq, Some(0));
+    update_highest_received(&mut session, u32::MAX);
+    assert_eq!(session.highest_received_seq, Some(0));
+}