test: fix flaky test_request_queue_unlock_requests

Wait for the locks to propagate before unlocking, polling list_head via
poll_until_condition until the locked requests drop out of the queue head,
rather than unlocking immediately after list_and_lock_head returns.

Author: vdusek

tests/integration/test_request_queue.py

@@ -12,6 +12,7 @@
     get_random_string,
     maybe_await,
     maybe_sleep,
+    poll_until_condition,
 )
 from apify_client._models import (
     BatchAddResult,
@@ -560,6 +561,18 @@ async def test_request_queue_unlock_requests(client: ApifyClient | ApifyClientAs
         assert isinstance(result, LockedRequestQueueHead)
         lock_response = result
         assert len(lock_response.items) == 3
+        locked_ids = {item.id for item in lock_response.items}
+
+        # Wait for the locks to propagate before unlocking (eventual consistency): the lock-head response
+        # is acknowledged before all three lock writes are visible to subsequent reads, so unlocking
+        # immediately can see fewer locks than were just acquired. Locked requests are excluded from the
+        # queue head, so poll `list_head` until none of the locked requests reappear there, rather than
+        # guessing a fixed sleep.
+        async def all_locks_visible() -> bool:
+            head = await maybe_await(rq_client.list_head(limit=5))
+            return isinstance(head, RequestQueueHead) and locked_ids.isdisjoint(item.id for item in head.items)
+
+        await poll_until_condition(all_locks_visible, timeout=30, poll_interval=1)
 
         # Unlock all requests
         unlock_response = await maybe_await(rq_client.unlock_requests())