diff --git a/crates/knot-proxy/src/breaker.rs b/crates/knot-proxy/src/breaker.rs
index 881f569..4b6f6b6 100644
--- a/crates/knot-proxy/src/breaker.rs
+++ b/crates/knot-proxy/src/breaker.rs
@@ -144,6 +144,14 @@ impl Drop for BreakerPermit {
     }
 }
 
+#[cfg(test)]
+impl BreakerPermit {
+    fn record_failure_at(mut self, now: Instant) {
+        self.resolved = true;
+        self.breaker.record_failure_at(now);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -187,12 +195,13 @@ mod tests {
     #[test]
     fn cooldown_admits_one_trial_only() {
         let b = breaker(1, 50);
-        b.record_failure();
-        assert!(b.try_acquire().is_err());
-        std::thread::sleep(Duration::from_millis(60));
-        let trial = b.try_acquire().expect("trial admitted after cooldown");
+        let t0 = Instant::now();
+        let after = t0 + Duration::from_millis(60);
+        b.record_failure_at(t0);
+        assert!(b.try_acquire_at(t0).is_err());
+        let trial = b.try_acquire_at(after).expect("trial admitted after cooldown");
         assert!(
-            b.try_acquire().is_err(),
+            b.try_acquire_at(after).is_err(),
             "second concurrent half-open call must be rejected",
         );
         trial.record_success();
@@ -201,11 +210,14 @@ mod tests {
     #[test]
     fn half_open_failure_reopens() {
         let b = breaker(1, 50);
-        b.record_failure();
-        std::thread::sleep(Duration::from_millis(60));
-        b.try_acquire().expect("trial admitted").record_failure();
+        let t0 = Instant::now();
+        let after = t0 + Duration::from_millis(60);
+        b.record_failure_at(t0);
+        b.try_acquire_at(after)
+            .expect("trial admitted")
+            .record_failure_at(after);
         assert!(
-            b.try_acquire().is_err(),
+            b.try_acquire_at(after).is_err(),
             "half-open failure must reopen breaker",
         );
     }
@@ -213,11 +225,12 @@ mod tests {
     #[test]
     fn half_open_success_closes() {
         let b = breaker(1, 50);
-        b.record_failure();
-        std::thread::sleep(Duration::from_millis(60));
-        b.try_acquire().expect("trial admitted").record_success();
-        b.try_acquire().expect("closed").record_success();
-        b.try_acquire().expect("closed").record_success();
+        let t0 = Instant::now();
+        let after = t0 + Duration::from_millis(60);
+        b.record_failure_at(t0);
+        b.try_acquire_at(after).expect("trial admitted").record_success();
+        b.try_acquire_at(after).expect("closed").record_success();
+        b.try_acquire_at(after).expect("closed").record_success();
     }
 
     #[test]
@@ -244,10 +257,11 @@ mod tests {
     #[test]
     fn dropped_half_open_permit_closes_breaker() {
         let b = breaker(1, 50);
-        b.record_failure();
-        std::thread::sleep(Duration::from_millis(60));
-        drop(b.try_acquire().expect("trial admitted"));
-        b.try_acquire()
+        let t0 = Instant::now();
+        let after = t0 + Duration::from_millis(60);
+        b.record_failure_at(t0);
+        drop(b.try_acquire_at(after).expect("trial admitted"));
+        b.try_acquire_at(after)
             .expect("dropped half-open permit must close breaker")
             .record_success();
     }