diff --git a/tests/unit/fair_queue_test.cc b/tests/unit/fair_queue_test.cc
index bbcf5f7942c..12ca5aec858 100644
--- a/tests/unit/fair_queue_test.cc
+++ b/tests/unit/fair_queue_test.cc
@@ -75,7 +75,16 @@ class test_env {
     }
 
     void drain() {
-        do {} while (tick() != 0);
+        while (true) {
+            if (tick()) {
+                continue;
+            }
+            auto ts = _fq.next_pending_aio();
+            if (ts == std::chrono::steady_clock::time_point::max()) {
+                break;
+            }
+            sleep(ts - std::chrono::steady_clock::now()).get();
+        }
     }
 public:
     test_env(unsigned capacity)
@@ -90,27 +99,27 @@ class test_env {
     // Because of this property, one useful use of tick() is to implement a drain()
     // method (see above) in which all requests currently sent to the queue are drained
     // before the queue is destroyed.
-    unsigned tick(unsigned n = 1) {
+    unsigned tick(unsigned n = 0) {
         unsigned processed = 0;
-        _fg.replenish_capacity(_fg.replenished_ts() + std::chrono::microseconds(1));
-        _fq.dispatch_requests([] (fair_queue_entry& ent) {
-            boost::intrusive::get_parent_from_member(&ent, &request::fqent)->submit();
-        });
+        while (true) {
+            _fg.replenish_capacity(_fg.replenished_ts() + std::chrono::microseconds(1));
+            _fq.dispatch_requests([] (fair_queue_entry& ent) {
+                boost::intrusive::get_parent_from_member(&ent, &request::fqent)->submit();
+            });
 
-        for (unsigned i = 0; i < n; ++i) {
             std::vector<request> curr;
             curr.swap(_inflight);
 
             for (auto& req : curr) {
-                processed++;
-                _results[req.index]++;
+                if (processed < n) {
+                    _results[req.index]++;
+                }
                 _fq.notify_request_finished(req.fqent.capacity());
+                processed++;
+            }
+            if (processed >= n) {
+                break;
             }
-
-            _fg.replenish_capacity(_fg.replenished_ts() + std::chrono::microseconds(1));
-            _fq.dispatch_requests([] (fair_queue_entry& ent) {
-                boost::intrusive::get_parent_from_member(&ent, &request::fqent)->submit();
-            });
         }
         return processed;
     }