File

spec/util_hashring_spec.lua @ 12480:7e9ebdc75ce4

net: isolate LuaSec-specifics For this, various accessor functions are now provided directly on the sockets, which reach down into the LuaSec implementation to obtain the information. While this may seem of little gain at first, it hides the implementation detail of the LuaSec+LuaSocket combination that the actual socket and the TLS layer are separate objects. The net gain here is that an alternative implementation does not have to emulate that specific implementation detail and "only" has to expose LuaSec-compatible data structures on the new functions.
author Jonas Schäfer <jonas@wielicki.name>
date Wed, 27 Apr 2022 17:44:14 +0200
parent 10007:de43ca319184
child 12794:249b01adc54a
line wrap: on
line source

local hashring = require "util.hashring";

describe("util.hashring", function ()

	local sha256 = require "util.hashes".sha256;

	local ring = hashring.new(128, sha256);

	it("should fail to get a node that does not exist", function ()
		assert.is_nil(ring:get_node("foo"))
	end);

	it("should support adding nodes", function ()
		ring:add_node("node1");
	end);

	it("should return a single node for all keys if only one node exists", function ()
		for i = 1, 100 do
			assert.is_equal("node1", ring:get_node(tostring(i)))
		end
	end);

	it("should support adding a second node", function ()
		ring:add_node("node2");
	end);

	it("should fail to remove a non-existent node", function ()
		assert.is_falsy(ring:remove_node("node3"));
	end);

	it("should succeed to remove a node", function ()
		assert.is_truthy(ring:remove_node("node1"));
	end);

	it("should return the only node for all keys", function ()
		for i = 1, 100 do
			assert.is_equal("node2", ring:get_node(tostring(i)))
		end
	end);

	it("should support adding multiple nodes", function ()
		ring:add_nodes({ "node1", "node3", "node4", "node5" });
	end);

	it("should disrupt a minimal number of keys on node removal", function ()
		local orig_ring = ring:clone();
		local node_tallies = {};

		local n = 1000;

		for i = 1, n do
			local key = tostring(i);
			local node = ring:get_node(key);
			node_tallies[node] = (node_tallies[node] or 0) + 1;
		end

		--[[
		for node, key_count in pairs(node_tallies) do
			print(node, key_count, ("%.2f%%"):format((key_count/n)*100));
		end
		]]

		ring:remove_node("node5");

		local disrupted_keys = 0;
		for i = 1, n do
			local key = tostring(i);
			if orig_ring:get_node(key) ~= ring:get_node(key) then
				disrupted_keys = disrupted_keys + 1;
			end
		end
		assert.is_equal(node_tallies["node5"], disrupted_keys);
	end);

	it("should support removing multiple nodes", function ()
		ring:remove_nodes({"node2", "node3", "node4", "node5"});
	end);

	it("should return a single node for all keys if only one node remains", function ()
		for i = 1, 100 do
			assert.is_equal("node1", ring:get_node(tostring(i)))
		end
	end);

end);