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spec/util_array_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 11787:3ae6fa901a8b
child 13245:ffe4adbd2af9
line wrap: on
line source

local array = require "util.array";
describe("util.array", function ()
	describe("creation", function ()
		describe("from table", function ()
			it("works", function ()
				local a = array({"a", "b", "c"});
				assert.same({"a", "b", "c"}, a);
			end);
		end);

		describe("from iterator", function ()
			it("works", function ()
				-- collects the first value, ie the keys
				local a = array(ipairs({true, true, true}));
				assert.same({1, 2, 3}, a);
			end);
		end);

		describe("collect", function ()
			it("works", function ()
				-- collects the first value, ie the keys
				local a = array.collect(ipairs({true, true, true}));
				assert.same({1, 2, 3}, a);
			end);
		end);

	end);

	describe("metatable", function ()
		describe("operator", function ()
			describe("addition", function ()
				it("works", function ()
					local a = array({ "a", "b" });
					local b = array({ "c", "d" });
					assert.same({"a", "b", "c", "d"}, a + b);
				end);
			end);

			describe("equality", function ()
				it("works", function ()
					local a1 = array({ "a", "b" });
					local a2 = array({ "a", "b" });
					local b = array({ "c", "d" });
					assert.truthy(a1 == a2);
					assert.falsy(a1 == b);
					assert.falsy(a1 == { "a", "b" }, "Behavior of metatables changed in Lua 5.3");
				end);
			end);

			describe("division", function ()
				it("works", function ()
					local a = array({ "a", "b", "c" });
					local b = a / function (i) if i ~= "b" then return i .. "x" end end;
					assert.same({ "ax", "cx" }, b);
				end);
			end);

		end);
	end);

	describe("methods", function ()
		describe("map", function ()
			it("works", function ()
				local a = array({ "a", "b", "c" });
				local b = a:map(string.upper);
				assert.same({ "A", "B", "C" }, b);
			end);
		end);

		describe("filter", function ()
			it("works", function ()
				local a = array({ "a", "b", "c" });
				a:filter(function (i) return i ~= "b" end);
				assert.same({ "a", "c" }, a);
			end);
		end);

		describe("sort", function ()
			it("works", function ()
				local a = array({ 5, 4, 3, 1, 2, });
				a:sort();
				assert.same({ 1, 2, 3, 4, 5, }, a);
			end);
		end);

		describe("unique", function ()
			it("works", function ()
				local a = array({ "a", "b", "c", "c", "a", "b" });
				a:unique();
				assert.same({ "a", "b", "c" }, a);
			end);
		end);

		describe("pluck", function ()
			it("works", function ()
				local a = array({ { a = 1, b = -1 }, { a = 2, b = -2 }, });
				a:pluck("a");
				assert.same({ 1, 2 }, a);
			end);
		end);


		describe("reverse", function ()
			it("works", function ()
				local a = array({ "a", "b", "c" });
				a:reverse();
				assert.same({ "c", "b", "a" }, a);
			end);
		end);

		-- TODO :shuffle

		describe("append", function ()
			it("works", function ()
				local a = array({ "a", "b", "c" });
				a:append(array({ "d", "e", }));
				assert.same({ "a", "b", "c", "d", "e" }, a);
			end);
		end);

		describe("push", function ()
			it("works", function ()
				local a = array({ "a", "b", "c" });
				a:push("d"):push("e");
				assert.same({ "a", "b", "c", "d", "e" }, a);
			end);
		end);

		describe("pop", function ()
			it("works", function ()
				local a = array({ "a", "b", "c" });
				assert.equal("c", a:pop());
				assert.same({ "a", "b", }, a);
			end);
		end);

		describe("concat", function ()
			it("works", function ()
				local a = array({ "a", "b", "c" });
				assert.equal("a,b,c", a:concat(","));
			end);
		end);

		describe("length", function ()
			it("works", function ()
				local a = array({ "a", "b", "c" });
				assert.equal(3, a:length());
			end);
		end);

		describe("slice", function ()
			it("works", function ()
				local a = array({ "a", "b", "c" });
				assert.equal(array.slice(a, 1, 2), array{ "a", "b" });
				assert.equal(array.slice(a, 1, 3), array{ "a", "b", "c" });
				assert.equal(array.slice(a, 2, 3), array{ "b", "c" });
				assert.equal(array.slice(a, 2), array{ "b", "c" });
				assert.equal(array.slice(a, -4), array{ "a", "b", "c" });
				assert.equal(array.slice(a, -3), array{ "a", "b", "c" });
				assert.equal(array.slice(a, -2), array{ "b", "c" });
				assert.equal(array.slice(a, -1), array{ "c" });
			end);

			it("can mutate", function ()
				local a = array({ "a", "b", "c" });
				assert.equal(a:slice(-1), array{"c"});
				assert.equal(a, array{"c"});
			end);
		end);
	end);

	-- TODO The various array.foo(array ina, array outa) functions
end);