add test case for server sending GOAWAY before opening a stream

spec/h2_stream_spec.lua

@@ -5,6 +5,7 @@ describe("http.h2_stream", function()
 	local cqueues = require "cqueues"
 	local ca = require "cqueues.auxlib"
 	local cs = require "cqueues.socket"
+	local cc = require "cqueues.condition"
 	local function new_pair()
 		local s, c = ca.assert(cs.pair())
 		s = assert(h2_connection.new(s, "server"))
@@ -265,4 +266,27 @@ describe("http.h2_stream", function()
 			assert.truthy(cq:empty())
 		end)
 	end)
+	it("errors when a server sends goaway before a stream is opened", function()
+		local s, c = new_pair()
+		local cq = cqueues.new()
+		local cond = cc.new()
+		local req_headers = new_headers()
+		req_headers:append(":method", "GET")
+		req_headers:append(":scheme", "http")
+		req_headers:append(":path", "/")
+		cq:wrap(function()
+			assert(cond:wait())
+			local stream = c:new_stream()
+			assert.falsy(stream)
+		end)
+		cq:wrap(function()
+			-- ensure client coroutine runs first
+			cqueues.sleep(0.1)
+			assert(s:write_goaway_frame(nil,h2_error.errors.INTERNAL_ERROR.code))
+			cond:signal(1)
+		end)
+		assert_loop(cq, TEST_TIMEOUT)
+		s:close()
+		c:close()
+	end)
 end)