From d0a430fddd7ba233aaeea4d60b9c07227687b32b Mon Sep 17 00:00:00 2001
From: Richard McDaniel <1130888+rmcdaniel@users.noreply.github.com>
Date: Sat, 24 Oct 2026 11:26:25 +0000
Subject: [PATCH] Compare activity lease renewals as instants, not RFC3339 text

heartbeat_renews_only_progress_deadline_and_cannot_resurrect_elapsed_authority
compared two lease_expires_at strings. Native times are whole
milliseconds and serialize without a fraction on a whole second, so a
claim lease of ...:26Z sorted after a renewal of ...:26.045Z and the
assertion failed about one run in a thousand (train #729, PostgreSQL 17
job 120852521096). The test now parses both and reports the values.
---
 rust/tests/execution/activity_deadlines.rs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/rust/tests/execution/activity_deadlines.rs b/rust/tests/execution/activity_deadlines.rs
index ea2d4d3a9..c67b5f724 100644
--- a/rust/tests/execution/activity_deadlines.rs
+++ b/rust/tests/execution/activity_deadlines.rs
@@ -483,9 +483,14 @@ async fn heartbeat_renews_only_progress_deadline_and_cannot_resurrect_elapsed_au
     assert_eq!(after.0, initial.0, "Start-to-close deadline remains fixed");
     assert!(after.1 > initial.1, "Heartbeat deadline advances");
     assert_eq!(after.2, initial.2, "Lifecycle deadline remains fixed");
+    // Compare instants, not text: a lease on a whole second is written
+    // without a fraction ("...:26Z"), which sorts after "...:26.045Z".
+    let instant = |value: &Value| chrono::DateTime::parse_from_rfc3339(value.as_str().unwrap()).unwrap();
     assert!(
-        renewed.1["lease_expires_at"].as_str().unwrap()
-            > activity["lease_expires_at"].as_str().unwrap()
+        instant(&renewed.1["lease_expires_at"]) > instant(&activity["lease_expires_at"]),
+        "{} renews {}",
+        renewed.1["lease_expires_at"],
+        activity["lease_expires_at"]
     );
     let prefix = run_history(&app, &started["workflow_id"], &started["run_id"]).await;
     database