--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spec/util_array_spec.lua	Thu Nov 05 22:31:25 2020 +0100
@@ -0,0 +1,155 @@
+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);
+
+	end);
+
+	-- TODO The various array.foo(array ina, array outa) functions
+end);
+