1 files changed, 7 insertions, 0 deletions
diff --git a/test/fiber/scheduler.rb b/test/fiber/scheduler.rb
index 322564fe6d..3fd41ef6f1 100644
--- a/test/fiber/scheduler.rb
+++ b/test/fiber/scheduler.rb
@@ -197,6 +197,13 @@ class Scheduler
     @writable.delete(io)
   end
 
+  def io_select(...)
+    # Emulate the operation using a non-blocking thread:
+    Thread.new do
+      IO.select(...)
+    end.value
+  end
+
   # Used for Kernel#sleep and Thread::Mutex#sleep
   def kernel_sleep(duration = nil)
     # $stderr.puts [__method__, duration, Fiber.current].inspect