diff --git a/test/natalie/fiber/shared/scheduler.rb b/test/natalie/fiber/shared/scheduler.rb
index a8bc6e6688..c3749e7507 100644
--- a/test/natalie/fiber/shared/scheduler.rb
+++ b/test/natalie/fiber/shared/scheduler.rb
@@ -6,10 +6,11 @@ def initialize
   def run
     until @waiting.empty?
       fiber, = @waiting.find { |fiber, timeout| fiber.alive? && timeout <= current_time }
-      next if fiber.nil?
 
-      @waiting.delete(fiber)
-      fiber.resume
+      unless fiber.nil?
+        @waiting.delete(fiber)
+        fiber.resume
+      end
     end
   end