diff --git a/ruby/lib/ci/queue/redis/worker.rb b/ruby/lib/ci/queue/redis/worker.rb
index 9445f339..d311be39 100644
--- a/ruby/lib/ci/queue/redis/worker.rb
+++ b/ruby/lib/ci/queue/redis/worker.rb
@@ -168,9 +168,9 @@ def raise_on_mismatching_test(test)
         end
 
         def reserve
-          test = (try_to_reserve_lost_test || try_to_reserve_test)
-          reserved_tests << test
-          test
+          (try_to_reserve_lost_test || try_to_reserve_test).tap do |test|
+            reserved_tests << test if test
+          end
         end
 
         def try_to_reserve_test