1 files changed, 37 insertions, 0 deletions
diff --git a/spec/ruby/library/fiber/transfer_spec.rb b/spec/ruby/library/fiber/transfer_spec.rb
index ad501c1d74..541aafc29d 100644
--- a/spec/ruby/library/fiber/transfer_spec.rb
+++ b/spec/ruby/library/fiber/transfer_spec.rb
@@ -47,5 +47,42 @@ with_feature :fiber_library do
       fiber = Fiber.new { fiber.resume }
       lambda { fiber.transfer }.should raise_error(FiberError)
     end
+
+    it "works if Fibers in different Threads each transfer to a Fiber in the same Thread" do
+      # This catches a bug where Fibers are running on a thread-pool
+      # and Fibers from a different Ruby Thread reuse the same native thread.
+      # Caching the Ruby Thread based on the native thread is not correct in that case,
+      # and the check for "fiber called across threads" in Fiber#transfer
+      # might be incorrect based on that.
+      2.times do
+        Thread.new do
+          io_fiber = Fiber.new do |calling_fiber|
+            calling_fiber.transfer
+          end
+          io_fiber.transfer(Fiber.current)
+          value = Object.new
+          io_fiber.transfer(value).should equal value
+        end.join
+      end
+    end
+
+    it "transfers control between a non-main thread's root fiber to a child fiber and back again" do
+      states = []
+      thread = Thread.new do
+        f1 = Fiber.new do |f0|
+          states << 0
+          value2 = f0.transfer(1)
+          states << value2
+          3
+        end
+
+        value1 = f1.transfer(Fiber.current)
+        states << value1
+        value3 = f1.transfer(2)
+        states << value3
+      end
+      thread.join
+      states.should == [0, 1, 2, 3]
+    end
   end
 end