fix(router): address greptile review on least-busy tie-breaking

- Remove misleading `in ("1", "2")` assertion in stale-entry test; "2"
  can never be returned since "1" is always the unique minimum after
  filtering the stale "0" entry
- Replace unreachable `return random.choice(healthy_deployments)` fallback
  with explicit ValueError guards; the old fallback was dead code after
  the healthy-ID filter ensured min_deployment_ids is always non-empty,
  and still raised IndexError on an empty list anyway

Made-with: Cursor

litellm/router_strategy/least_busy.py

@@ -215,13 +215,15 @@ class LeastBusyLoggingHandler(CustomLogger):
             elif v == min_traffic:
                 min_deployment_ids.append(k)
 
-        if min_deployment_ids:
-            chosen_id = random.choice(min_deployment_ids)
-            for m in healthy_deployments:
-                if m["model_info"]["id"] == chosen_id:
-                    return m
+        if not min_deployment_ids:
+            raise ValueError("No healthy deployments available")
 
-        return random.choice(healthy_deployments)
+        chosen_id = random.choice(min_deployment_ids)
+        for m in healthy_deployments:
+            if m["model_info"]["id"] == chosen_id:
+                return m
+
+        raise ValueError(f"Chosen deployment id {chosen_id!r} not found in healthy_deployments")
 
     def get_available_deployments(
         self,

tests/test_litellm/router_strategy/test_least_busy.py

@@ -89,7 +89,6 @@ class TestLeastBusyTieBreaking:
                 healthy_deployments=healthy,
                 all_deployments=dict(counts_with_stale),
             )
-            assert chosen["model_info"]["id"] in ("1", "2")
             assert chosen["model_info"]["id"] == "1"