public void Test1()
        {
            var inputs = new List <string>
            {
                "Step C must be finished before step A can begin.",
                "Step C must be finished before step F can begin.",
                "Step A must be finished before step B can begin.",
                "Step A must be finished before step D can begin.",
                "Step B must be finished before step E can begin.",
                "Step D must be finished before step E can begin.",
                "Step F must be finished before step E can begin.",
            };

            var rules = Functions.ProcessRules(inputs);

            var result = Functions.DetermineExecutionOrder(rules);

            Assert.AreEqual("CABDFE", result);
        }