loopd: a failed heartbeat still advances last_heartbeat

Co-Authored-By: ornith-1.5-35b-a3b <agent@wntrmute.dev>

crates/loopd/tests/scheduler_heartbeat_failed.rs

@@ -0,0 +1,50 @@
+//! A failed heartbeat turn still advances `last_heartbeat`. Do not edit.
+
+mod support;
+
+use bxcore::Timestamp;
+use loopd::channel::Context;
+use loopd::llama::Client;
+use loopd::memory::NoMemory;
+use loopd::scheduler::{Scheduler, TickWork};
+use loopd::tools::Registry;
+use std::sync::Arc;
+use support::{FakeServer, Home, Reply, ScriptedPort};
+
+const CHAT: &str = "/v1/chat/completions";
+const PROMPT: &str = "Look around.\n";
+
+fn ts(s: &str) -> Timestamp {
+    Timestamp::parse(s).unwrap()
+}
+
+fn world() -> (Home, FakeServer, Arc<Context>) {
+    let home = Home::new();
+    home.write("heartbeat.md", PROMPT);
+    home.write("compact.md", "Summarise.\n");
+    let server = FakeServer::start();
+    let mut cfg = home.config(&server.socket);
+    cfg.heartbeat.every_s = 60;
+    cfg.heartbeat.prompt = home.dir.join("heartbeat.md");
+    server.route(CHAT, vec![Reply::fixture("bad_request")]);
+    let ctx = Arc::new(Context::new(
+        cfg.clone(),
+        Client::new(cfg),
+        Box::new(ScriptedPort::new(vec![])),
+        Registry::m2b(),
+        Box::new(NoMemory),
+    ));
+    (home, server, ctx)
+}
+
+#[test]
+fn a_failed_heartbeat_turn_still_advances_last_heartbeat() {
+    let (_home, server, ctx) = world();
+    let mut sched = Scheduler::new(ts("2026-10-03T07:00:00.000Z"));
+    let work = sched.tick(&ctx, ts("2026-10-03T07:01:00.000Z"));
+    assert_eq!(work, vec![TickWork::Heartbeat]);
+    assert_eq!(server.requests_to(CHAT).len(), 1);
+    let work = sched.tick(&ctx, ts("2026-10-03T07:01:30.000Z"));
+    assert!(work.is_empty(), "{work:?}");
+    assert_eq!(server.requests_to(CHAT).len(), 1);
+}