--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spec/util_datetime_spec.lua	Sun Nov 19 20:51:53 2017 +0100
@@ -0,0 +1,76 @@
+local util_datetime = require "util.datetime";
+
+describe("util.datetime", function ()
+	it("should have been loaded", function ()
+		assert.is_table(util_datetime);
+	end);
+	describe("#date", function ()
+		local date = util_datetime.date;
+		it("should exist", function ()
+			assert.is_function(date);
+		end);
+		it("should return a string", function ()
+			assert.is_string(date());
+		end);
+		it("should look like a date", function ()
+			assert.truthy(string.find(date(), "^%d%d%d%d%-%d%d%-%d%d$"));
+		end);
+		it("should work", function ()
+			assert.equals(date(1136239445), "2006-01-02");
+		end);
+	end);
+	describe("#time", function ()
+		local time = util_datetime.time;
+		it("should exist", function ()
+			assert.is_function(time);
+		end);
+		it("should return a string", function ()
+			assert.is_string(time());
+		end);
+		it("should look like a timestamp", function ()
+			-- Note: Sub-second precision and timezones are ignored
+			assert.truthy(string.find(time(), "^%d%d:%d%d:%d%d"));
+		end);
+		it("should work", function ()
+			assert.equals(time(1136239445), "22:04:05");
+		end);
+	end);
+	describe("#datetime", function ()
+		local datetime = util_datetime.datetime;
+		it("should exist", function ()
+			assert.is_function(datetime);
+		end);
+		it("should return a string", function ()
+			assert.is_string(datetime());
+		end);
+		it("should look like a timestamp", function ()
+			-- Note: Sub-second precision and timezones are ignored
+			assert.truthy(string.find(datetime(), "^%d%d%d%d%-%d%d%-%d%dT%d%d:%d%d:%d%d"));
+		end);
+		it("should work", function ()
+			assert.equals(datetime(1136239445), "2006-01-02T22:04:05Z");
+		end);
+	end);
+	describe("#legacy", function ()
+		local legacy = util_datetime.legacy;
+		it("should exist", function ()
+			assert.is_function(legacy);
+		end);
+	end);
+	describe("#parse", function ()
+		local parse = util_datetime.parse;
+		it("should exist", function ()
+			assert.is_function(parse);
+		end);
+		it("should work", function ()
+			-- Timestamp used by Go
+			assert.equals(parse("2017-11-19T17:58:13Z"),     1511114293);
+			assert.equals(parse("2017-11-19T18:58:50+0100"), 1511114330);
+			assert.equals(parse("2006-01-02T15:04:05-0700"), 1136239445);
+		end);
+		it("should handle timezones", function ()
+			-- https://xmpp.org/extensions/xep-0082.html#example-2 and 3
+			assert.equals(parse("1969-07-21T02:56:15Z"), parse("1969-07-20T21:56:15-05:00"));
+		end);
+	end);
+end);