Reproduce Windows jobs failure on CI

core/sizedqueue/push_spec.rb

@@ -5,3 +5,44 @@
     SizedQueue.instance_method(:push).should == SizedQueue.instance_method(:<<)
   end
 end
+
+describe "SizedQueue#push with Fiber scheduler" do
+  require_relative '../fiber/fixtures/scheduler'
+
+  before :each do
+    Fiber.set_scheduler(FiberSpecs::LoggingScheduler.new)
+  end
+
+  after :each do
+    Fiber.set_scheduler(nil)
+  end
+
+  it "blocks through the scheduler while the queue is full" do
+    q = SizedQueue.new(1)
+    q << 1
+    pusher = Fiber.schedule { q << 2 }
+
+    Fiber.scheduler.events.last.should == { event: :block, fiber: pusher, args: [q, nil] }
+
+    popper = Fiber.schedule { q.pop.should == 1 }
+    Fiber.scheduler.events.last.should == { event: :unblock, fiber: popper, args: [q, pusher] }
+
+    [popper, pusher].each { |f| f.resume while f.alive? }
+    q.pop.should == 2
+  end
+
+  it "raises ClosedQueueError when the queue is closed while it blocks" do
+    q = SizedQueue.new(1)
+    q << 1
+    error = nil
+    pusher = Fiber.schedule do
+      q << 2
+    rescue ClosedQueueError => e
+      error = e
+    end
+
+    closer = Fiber.schedule { q.close }
+    [closer, pusher].each { |f| f.resume while f.alive? }
+    error.should.is_a?(ClosedQueueError)
+  end
+end