Add real URing io_wait priority event repro

Author: samuel-williams-shopify

test/io/event/selector/uring.rb

@@ -5,9 +5,50 @@
 
 require "io/event"
 require "io/event/selector"
+require "socket"
 
 describe IO::Event::Selector do
 	with "URing" do
+		it "does not resume io_wait with zero for an unrequested priority event" do
+			skip "URing is not available" unless subject.const_defined?(:URing)
+
+			uring = subject.const_get(:URing)
+			selector = uring.new(Fiber.current)
+
+			server = TCPServer.new("127.0.0.1", 0)
+			client = TCPSocket.new("127.0.0.1", server.addr[1])
+			peer = server.accept
+
+			result = nil
+
+			fiber = Fiber.new do
+				result = selector.io_wait(Fiber.current, client, IO::READABLE)
+			end
+
+			fiber.transfer
+
+			peer.send("!", Socket::MSG_OOB)
+			selector.select(0.1)
+
+			expect(result).not.to be == 0
+
+			if fiber.alive?
+				peer.write("x")
+
+				10.times do
+					selector.select(0.1)
+					break unless fiber.alive?
+				end
+
+				expect(result).to be == IO::READABLE
+			end
+		ensure
+			selector&.close
+			client&.close
+			peer&.close
+			server&.close
+		end
+
 		it "does not expose unmatched poll completions as integer zero from io_wait" do
 			skip "URing is not available" unless subject.const_defined?(:URing)