Test Driven FizzBuzz

Here is my solution when I apply TDD on FizzBuzz using C# :

class FizzBuzz
{
    private readonly List<Tuple<int, string>> rules;
    public FizzBuzz()
        : this(new Tuple<int, string>[0])
    {
    }
    public FizzBuzz(IEnumerable<Tuple<int, string>> rules)
    {
        this.rules = rules.ToList();
    }
    public string Convert(int i)
    {
        var label = string.Join("", rules.Where(r => i % r.Item1 == 0).Select(r => r.Item2));
        return label.Length > 0 ? label : i.ToString();
    }
}

[TestFixture]
public class FizzBuzzTest
{
    [TestCase(1, "1")]
    [TestCase(2, "2")]
    [TestCase(3, "3")]
    public void TestNoRule(int i, string value)
    {
        Assert.AreEqual(value, new FizzBuzz().Convert(i));
    }
    [TestCase(1, "1")]
    [TestCase(2, "2")]
    [TestCase(3, "Fizz")]
    public void TestFizz(int i, string value)
    {
        Assert.AreEqual(value, new FizzBuzz(new[] { new Tuple<int, string>(3, "Fizz") }).Convert(i));
    }
    [TestCase(1, "1")]
    [TestCase(2, "2")]
    [TestCase(3, "3")]
    [TestCase(4, "4")]
    [TestCase(5, "Buzz")]
    public void TestBuzz(int i, string value)
    {
        Assert.AreEqual(value, new FizzBuzz(new[] { new Tuple<int, string>(5, "Buzz") }).Convert(i));
    }
    [TestCase(15, "FizzBuzz")]
    public void TestFizzBuzz(int i, string value)
    {
        var rules = new[] {
            new Tuple<int, string>(3, "Fizz"),
            new Tuple<int, string>(5, "Buzz"),
        };
        Assert.AreEqual(value, new FizzBuzz(rules).Convert(i));
    }
    [Test] public void TestFizzBuzz1_100()
    {
        var rules = new[] {
            new Tuple<int, string>(3, "Fizz"),
            new Tuple<int, string>(5, "Buzz"),
        };
        var fizzBuzz = new FizzBuzz(rules);
        for (int i = 1; i < 100; i++)
            Console.WriteLine(fizzBuzz.Convert(i));
    }
}

See also :

• Advanced TDD (vimeo) by Uncle Bob at NDC 2014
• Railway oriented programming applied to fizzbuzz with F#