File

spec/util_hashring_spec.lua @ 12775:1dd468c63a3d

mod_blocklist: Add option 'migrate_legacy_blocking' to disable migration from mod_privacy Tiny performance improvement for new users by skipping this check. Most servers should have gone trough the migration for all active users long ago. As a suitable first step of phasing out this code, we make it possible to disable it first. Later it can be disabled by default, before finally the code is deleted.
author Kim Alvefur <zash@zash.se>
date Mon, 17 Oct 2022 15:20:06 +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);