diff --git a/core/fiber/set_scheduler_spec.rb b/core/fiber/set_scheduler_spec.rb
index b34aff873..64a9d70c6 100644
--- a/core/fiber/set_scheduler_spec.rb
+++ b/core/fiber/set_scheduler_spec.rb
@@ -3,8 +3,12 @@
 require "fiber"
 
 describe "Fiber.scheduler" do
+  required_methods = [:block, :unblock, :kernel_sleep, :io_wait]
+  ruby_version_is "4.1" do
+    required_methods << :fiber_interrupt
+  end
+
   it "validates the scheduler for required methods" do
-    required_methods = [:block, :unblock, :kernel_sleep, :io_wait]
     required_methods.each do |missing_method|
       scheduler = Object.new
       required_methods.difference([missing_method]).each do |method|
@@ -17,7 +21,6 @@
   end
 
   it "can set and get the scheduler" do
-    required_methods = [:block, :unblock, :kernel_sleep, :io_wait]
     scheduler = Object.new
     required_methods.each do |method|
       scheduler.define_singleton_method(method) {}
@@ -27,7 +30,6 @@
   end
 
   it "returns the scheduler after setting it" do
-    required_methods = [:block, :unblock, :kernel_sleep, :io_wait]
     scheduler = Object.new
     required_methods.each do |method|
       scheduler.define_singleton_method(method) {}
@@ -37,7 +39,6 @@
   end
 
   it "can remove the scheduler" do
-    required_methods = [:block, :unblock, :kernel_sleep, :io_wait]
     scheduler = Object.new
     required_methods.each do |method|
       scheduler.define_singleton_method(method) {}
@@ -52,4 +53,17 @@
     Fiber.set_scheduler(nil)
     Fiber.scheduler.should == nil
   end
+
+  it "closes the scheduler at exit, before any at_exit handler runs" do
+    code = <<-RUBY
+      scheduler = Object.new
+      #{required_methods}.each { |m| scheduler.define_singleton_method(m) {} }
+      scheduler.define_singleton_method(:close) { print "c" }
+
+      at_exit { print "a" }
+      Fiber.set_scheduler(scheduler)
+    RUBY
+
+    ruby_exe(code).should == "ca"
+  end
 end