describe("util.smqueue", function()

	local smqueue

	setup(function() smqueue = require "util.smqueue"; end)

	describe("#new()", function()

		it("should work", function()

			assert.has_error(function () smqueue.new(-1) end);

			assert.has_error(function () smqueue.new(0) end);

			assert.not_has_error(function () smqueue.new(1) end);

			local q = smqueue.new(10);

			assert.truthy(q);

		end)

	end)

	describe("#push()", function()

		it("should allow pushing many items", function()

			local q = smqueue.new(10);

			for i = 1, 20 do q:push(i); end

			assert.equal(20, q:count_unacked());

		end)

	end)

	describe("#resumable()", function()

		it("returns true while the queue is small", function()

			local q = smqueue.new(10);

			for i = 1, 10 do q:push(i); end

			assert.truthy(q:resumable());

			q:push(11);

			assert.falsy(q:resumable());

		end)

	end)

	describe("#ack", function()

		it("allows removing items", function()

			local q = smqueue.new(10);

			for i = 1, 10 do q:push(i); end

			assert.same({ 1; 2; 3 }, q:ack(3));

			assert.same({ 4; 5; 6 }, q:ack(6));

			assert.falsy(q:ack(3), "can't go backwards")

			assert.falsy(q:ack(100), "can't ack too many")

			for i = 11, 20 do q:push(i); end

			assert.same({ 11; 12 }, q:ack(12), "items are dropped");

		end)

	end)

	describe("#resume", function()

		it("iterates over current items", function()

			local q = smqueue.new(10);

			for i = 1, 12 do q:push(i); end

			assert.same({ 3; 4; 5; 6 }, q:ack(6));

			assert.truthy(q:resumable());

			local resume = {}

			for _, i in q:resume() do resume[i] = true end

			assert.same({ [7] = true; [8] = true; [9] = true; [10] = true; [11] = true; [12] = true }, resume);

		end)

	end)

	describe("#table", function ()

		it("produces a compat layer", function ()

			local q = smqueue.new(10);

			for i = 1,10 do q:push(i); end

			do

				local t = q:table();

				assert.same({ 1; 2; 3; 4; 5; 6; 7; 8; 9; 10 }, t);

			end

			do

				for i = 11,20 do q:push(i); end

				local t = q:table();

				assert.same({ 11; 12; 13; 14; 15; 16; 17; 18; 19; 20 }, t);

			end

			do

				q:ack(15);

				local t = q:table();

				assert.same({ 16; 17; 18; 19; 20 }, t);

			end

			do

				q:ack(20);

				local t = q:table();

				assert.same({}, t);

			end

		end)

	end)

end);