File

spec/util_cache_spec.lua @ 13134:638f627e707f

util.datamanager: Add O(1) list indexing with on-disk index Index file contains offsets and lengths of each item() which allows seeking directly to each item and reading it without parsing the entire file. Also allows tricks like binary search, assuming items have some defined order. We take advantage of the 1-based indexing in tables to store a magic header in the 0 position, so that table index 1 ends up at file index 1.
author Kim Alvefur <zash@zash.se>
date Tue, 11 May 2021 02:09:56 +0200
parent 12771:e9fcc69ea508
child 13174:8ec7b7d6556f
line wrap: on
line source


local cache = require "util.cache";

describe("util.cache", function()
	describe("#new()", function()
		it("should work", function()
			do
				local c = cache.new(1);
				assert.is_not_nil(c);

				assert.has_error(function ()
					cache.new(0);
				end);
				assert.has_error(function ()
					cache.new(-1);
				end);
				assert.has_error(function ()
					cache.new("foo");
				end);
			end

			local c = cache.new(5);

			local function expect_kv(key, value, actual_key, actual_value)
				assert.are.equal(key, actual_key, "key incorrect");
				assert.are.equal(value, actual_value, "value incorrect");
			end

			expect_kv(nil, nil, c:head());
			expect_kv(nil, nil, c:tail());

			assert.are.equal(c:count(), 0);

			c:set("one", 1)
			assert.are.equal(c:count(), 1);
			expect_kv("one", 1, c:head());
			expect_kv("one", 1, c:tail());

			c:set("two", 2)
			expect_kv("two", 2, c:head());
			expect_kv("one", 1, c:tail());

			c:set("three", 3)
			expect_kv("three", 3, c:head());
			expect_kv("one", 1, c:tail());

			c:set("four", 4)
			c:set("five", 5);
			assert.are.equal(c:count(), 5);
			expect_kv("five", 5, c:head());
			expect_kv("one", 1, c:tail());

			c:set("foo", nil);
			assert.are.equal(c:count(), 5);
			expect_kv("five", 5, c:head());
			expect_kv("one", 1, c:tail());

			assert.are.equal(c:get("one"), 1);
			expect_kv("five", 5, c:head());
			expect_kv("one", 1, c:tail());

			assert.are.equal(c:get("two"), 2);
			assert.are.equal(c:get("three"), 3);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);

			assert.are.equal(c:get("foo"), nil);
			assert.are.equal(c:get("bar"), nil);

			c:set("six", 6);
			assert.are.equal(c:count(), 5);
			expect_kv("six", 6, c:head());
			expect_kv("two", 2, c:tail());

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), 2);
			assert.are.equal(c:get("three"), 3);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);

			c:set("three", nil);
			assert.are.equal(c:count(), 4);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), 2);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);

			c:set("seven", 7);
			assert.are.equal(c:count(), 5);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), 2);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);
			assert.are.equal(c:get("seven"), 7);

			c:set("eight", 8);
			assert.are.equal(c:count(), 5);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), nil);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);
			assert.are.equal(c:get("seven"), 7);
			assert.are.equal(c:get("eight"), 8);

			c:set("four", 4);
			assert.are.equal(c:count(), 5);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), nil);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), 5);
			assert.are.equal(c:get("six"), 6);
			assert.are.equal(c:get("seven"), 7);
			assert.are.equal(c:get("eight"), 8);

			c:set("nine", 9);
			assert.are.equal(c:count(), 5);

			assert.are.equal(c:get("one"), nil);
			assert.are.equal(c:get("two"), nil);
			assert.are.equal(c:get("three"), nil);
			assert.are.equal(c:get("four"), 4);
			assert.are.equal(c:get("five"), nil);
			assert.are.equal(c:get("six"), 6);
			assert.are.equal(c:get("seven"), 7);
			assert.are.equal(c:get("eight"), 8);
			assert.are.equal(c:get("nine"), 9);

			do
				local keys = { "nine", "four", "eight", "seven", "six" };
				local values = { 9, 4, 8, 7, 6 };
				local i = 0;
				for k, v in c:items() do
					i = i + 1;
					assert.are.equal(k, keys[i]);
					assert.are.equal(v, values[i]);
				end
				assert.are.equal(i, 5);

				c:set("four", "2+2");
				assert.are.equal(c:count(), 5);

				assert.are.equal(c:get("one"), nil);
				assert.are.equal(c:get("two"), nil);
				assert.are.equal(c:get("three"), nil);
				assert.are.equal(c:get("four"), "2+2");
				assert.are.equal(c:get("five"), nil);
				assert.are.equal(c:get("six"), 6);
				assert.are.equal(c:get("seven"), 7);
				assert.are.equal(c:get("eight"), 8);
				assert.are.equal(c:get("nine"), 9);
			end

			do
				local keys = { "four", "nine", "eight", "seven", "six" };
				local values = { "2+2", 9, 8, 7, 6 };
				local i = 0;
				for k, v in c:items() do
					i = i + 1;
					assert.are.equal(k, keys[i]);
					assert.are.equal(v, values[i]);
				end
				assert.are.equal(i, 5);

				c:set("foo", nil);
				assert.are.equal(c:count(), 5);

				assert.are.equal(c:get("one"), nil);
				assert.are.equal(c:get("two"), nil);
				assert.are.equal(c:get("three"), nil);
				assert.are.equal(c:get("four"), "2+2");
				assert.are.equal(c:get("five"), nil);
				assert.are.equal(c:get("six"), 6);
				assert.are.equal(c:get("seven"), 7);
				assert.are.equal(c:get("eight"), 8);
				assert.are.equal(c:get("nine"), 9);
			end

			do
				local keys = { "four", "nine", "eight", "seven", "six" };
				local values = { "2+2", 9, 8, 7, 6 };
				local i = 0;
				for k, v in c:items() do
					i = i + 1;
					assert.are.equal(k, keys[i]);
					assert.are.equal(v, values[i]);
				end
				assert.are.equal(i, 5);

				c:set("four", nil);

				assert.are.equal(c:get("one"), nil);
				assert.are.equal(c:get("two"), nil);
				assert.are.equal(c:get("three"), nil);
				assert.are.equal(c:get("four"), nil);
				assert.are.equal(c:get("five"), nil);
				assert.are.equal(c:get("six"), 6);
				assert.are.equal(c:get("seven"), 7);
				assert.are.equal(c:get("eight"), 8);
				assert.are.equal(c:get("nine"), 9);
			end

			do
				local keys = { "nine", "eight", "seven", "six" };
				local values = { 9, 8, 7, 6 };
				local i = 0;
				for k, v in c:items() do
					i = i + 1;
					assert.are.equal(k, keys[i]);
					assert.are.equal(v, values[i]);
				end
				assert.are.equal(i, 4);
			end

			do
				local evicted_key, evicted_value;
				local c2 = cache.new(3, function (_key, _value)
					evicted_key, evicted_value = _key, _value;
				end);
				local function set(k, v, should_evict_key, should_evict_value)
					evicted_key, evicted_value = nil, nil;
					c2:set(k, v);
					assert.are.equal(evicted_key, should_evict_key);
					assert.are.equal(evicted_value, should_evict_value);
				end
				set("a", 1)
				set("a", 1)
				set("a", 1)
				set("a", 1)
				set("a", 1)

				set("b", 2)
				set("c", 3)
				set("b", 2)
				set("d", 4, "a", 1)
				set("e", 5, "c", 3)
			end

			do
				local evicted_key, evicted_value;
				local c3 = cache.new(1, function (_key, _value)
					evicted_key, evicted_value = _key, _value;
					if _key == "a" then
						-- Sanity check for what we're evicting
						assert.are.equal(_key, "a");
						assert.are.equal(_value, 1);
						-- We're going to block eviction of this key/value, so set to nil...
						evicted_key, evicted_value = nil, nil;
						-- Returning false to block eviction
						return false
					end
				end);
				local function set(k, v, should_evict_key, should_evict_value)
					evicted_key, evicted_value = nil, nil;
					local ret = c3:set(k, v);
					assert.are.equal(evicted_key, should_evict_key);
					assert.are.equal(evicted_value, should_evict_value);
					return ret;
				end
				set("a", 1)
				set("a", 1)
				set("a", 1)
				set("a", 1)
				set("a", 1)

				-- Our on_evict prevents "a" from being evicted, causing this to fail...
				assert.are.equal(set("b", 2), false, "Failed to prevent eviction, or signal result");

				expect_kv("a", 1, c3:head());
				expect_kv("a", 1, c3:tail());

				-- Check the final state is what we expect
				assert.are.equal(c3:get("a"), 1);
				assert.are.equal(c3:get("b"), nil);
				assert.are.equal(c3:count(), 1);
			end


			local c4 = cache.new(3, false);

			assert.are.equal(c4:set("a", 1), true);
			assert.are.equal(c4:set("a", 1), true);
			assert.are.equal(c4:set("a", 1), true);
			assert.are.equal(c4:set("a", 1), true);
			assert.are.equal(c4:set("b", 2), true);
			assert.are.equal(c4:set("c", 3), true);
			assert.are.equal(c4:set("d", 4), false);
			assert.are.equal(c4:set("d", 4), false);
			assert.are.equal(c4:set("d", 4), false);

			expect_kv("c", 3, c4:head());
			expect_kv("a", 1, c4:tail());

			local c5 = cache.new(3, function (k, v) --luacheck: ignore 212/v
				if k == "a" then
					return nil;
				elseif k == "b" then
					return true;
				end
				return false;
			end);

			assert.are.equal(c5:set("a", 1), true);
			assert.are.equal(c5:set("a", 1), true);
			assert.are.equal(c5:set("a", 1), true);
			assert.are.equal(c5:set("a", 1), true);
			assert.are.equal(c5:set("b", 2), true);
			assert.are.equal(c5:set("c", 3), true);
			assert.are.equal(c5:set("d", 4), true); -- "a" evicted (cb returned nil)
			assert.are.equal(c5:set("d", 4), true); -- nop
			assert.are.equal(c5:set("d", 4), true); -- nop
			assert.are.equal(c5:set("e", 5), true); -- "b" evicted (cb returned true)
			assert.are.equal(c5:set("f", 6), false); -- "c" won't evict (cb returned false)

			expect_kv("e", 5, c5:head());
			expect_kv("c", 3, c5:tail());

		end);

		it(":table works", function ()
			local t = cache.new(3):table();
			assert.is.table(t);
			t["a"] = "1";
			assert.are.equal(t["a"], "1");
			t["b"] = "2";
			assert.are.equal(t["b"], "2");
			t["c"] = "3";
			assert.are.equal(t["c"], "3");
			t["d"] = "4";
			assert.are.equal(t["d"], "4");
			assert.are.equal(t["a"], nil);

				local i = spy.new(function () end);
				for k, v in pairs(t) do
					i(k,v)
				end
				assert.spy(i).was_called();
				assert.spy(i).was_called_with("b", "2");
				assert.spy(i).was_called_with("c", "3");
				assert.spy(i).was_called_with("d", "4");
		end);

		local function vs(t)
			local vs_ = {};
			for v in t:values() do
				vs_[#vs_+1] = v;
			end
			return vs_;
		end

		it(":values works", function ()
			local t = cache.new(3);
			t:set("k1", "v1");
			t:set("k2", "v2");
			assert.same({"v2", "v1"}, vs(t));
			t:set("k3", "v3");
			assert.same({"v3", "v2", "v1"}, vs(t));
			t:set("k4", "v4");
			assert.same({"v4", "v3", "v2"}, vs(t));
		end);

		it(":resize works", function ()
			local c = cache.new(5);
			for i = 1, 5 do
				c:set(("k%d"):format(i), ("v%d"):format(i));
			end
			assert.same({"v5", "v4", "v3", "v2", "v1"}, vs(c));
			assert.has_error(function ()
				c:resize(-1);
			end);
			assert.has_error(function ()
				c:resize(0);
			end);
			assert.has_error(function ()
				c:resize("foo");
			end);
			c:resize(3);
			assert.same({"v5", "v4", "v3"}, vs(c));
		end);
	end);
end);