public void DeadlineCommand_should_parse_task_id()
        {
            var cmd = new DeadlineCommand("1 2017-12-25");

            Assert.AreEqual(new TaskId("1"), cmd.TaskId);
        }
        public void DeadlineCommand_should_parse_deadline()
        {
            var cmd = new DeadlineCommand("1 2017-12-25");

            Assert.AreEqual(new Deadline(new DateTime(2017, 12, 25)), cmd.Deadline);
        }