describe("channel module", function()
	it("should load",function()
		require("channel")
	end)
	describe("SimpleChannel",function()
		local channel = require("channel")
		it("should exist",function()
			assert(channel.SimpleChannel)
			assert(channel.SimpleChannel())
		end)
		it("should send messages",function()
			local sc = channel.SimpleChannel()
			assert(not sc:poll())
			sc:send("Hello")
			assert(sc:poll())
			assert(sc:recv() == "Hello")
		end)
		it("should send any string",function()
			local sc = channel.SimpleChannel()
			local rng = tostring(math.random())
			sc:send(rng)
			assert(sc:recv() == rng)
		end)
	end)
	describe("FaultyChannel",function()
		local channel = require("channel")
		it("should exist",function()
			assert(channel.FaultyChannel)
			assert(channel.FaultyChannel())
		end)
		it("can has a .time that allows it to time travel",function()
			channel.FaultyChannel.time = 0
			local fc = channel.FaultyChannel({
				loss_std = 0,
				avg_latency = 5
			})
			fc:send("a")
			assert(#fc.to_deliver == 1)
			assert(#fc.buffer == 0)
			channel.FaultyChannel.time = 10
			fc:pump()
			assert(#fc.to_deliver == 0)
			assert(#fc.buffer == 1)
			assert(fc:recv() == "a")
		end)
		it("has a normal() function that does normal distribution", function()
			local normal = channel.FaultyChannel.normal
			for i = 1, 20 do
				math.randomseed(i)
				local res = normal(nil,1,0.1)
				assert(res > 0.5 and res < 1.5)
			end
		end)
		it("can pump() with no side effects if time has not changed", function()
			channel.FaultyChannel.time = 0
			local fc = channel.FaultyChannel({
				loss = 0,
				avg_latency = 5
			})
			fc:send("a")
			assert(#fc.to_deliver == 1)
			assert(#fc.buffer == 0)
			fc:pump()
			assert(#fc.to_deliver == 1)
			assert(#fc.buffer == 0)
			channel.FaultyChannel.time = 4
			fc:pump()
			fc:send("b")
			assert(#fc.to_deliver == 2)
			assert(#fc.buffer == 0)
			channel.FaultyChannel.time = 6
			fc:pump()
			assert(#fc.to_deliver == 1)
			assert(#fc.buffer == 1)
		end)
		it("can be configured to not drop messages", function()
			channel.FaultyChannel.time = 0
			local fc = channel.FaultyChannel({
				avg_latency = 5,
				loss = 0
			})
			local i = 100
			for _ = 1,i do
				fc:send("a")
			end
			channel.FaultyChannel.time = 10
			local j = 0
			while fc:poll() do
				j = j + 1
				fc:recv()
			end
			assert(j == i)
		end)
		it("should drop messages sometimes",function()
			local fc = channel.FaultyChannel()
			local i = 100
			for _ = 1, i do
				fc:send("a")
			end
			-- Time forward
			--channel.FaultyChannel.time = math.huge
			local j = 0
			while fc:poll() do
				j = j + 1
				fc:recv()
			end
			assert(j < i)
		end)
		it("should keep a queue of messages", function()
			channel.FaultyChannel.time = 0
			local fc = channel.FaultyChannel({
				loss = 0,
				avg_latency=0,
				latency_std=0,
			})
			local i = 100
			for j = 1, i do
				fc:send(tostring(j))
			end
			channel.FaultyChannel.time = 1
			fc:pump()
			assert(#fc.to_deliver == 0)
			assert(#fc.buffer == i)
			for j = 1, i do
				assert(tonumber(fc:recv()) == j)
			end
			assert(not fc:poll())
		end)
		it("should deliver messages with different latencies", function()
			channel.FaultyChannel.time = 0
			local fc = channel.FaultyChannel({
				loss = 0,
				avg_latency = 20,
				latency_std = 5,
			})
			local i = 100
			for j = 1, i do
				fc:send(tostring(j))
			end
			local received = 0
			local increment = 0.5
			local last_received = nil
			local found_out_of_order = false
			while received < i do
				while fc:poll() do
					local recv = tonumber(fc:recv())
					if last_received and last_received < recv then
						found_out_of_order = true
					end
					last_received = recv
					received = received + 1
				end
				channel.FaultyChannel.time = channel.FaultyChannel.time + increment
			end
			assert(found_out_of_order)
		end)
	end)
end)