public void BasicTests()
{
Assert.AreEqual('f', Kata.AddLetters(new char[] { 'a', 'b', 'c' }));
Assert.AreEqual('z', Kata.AddLetters(new char[] { 'z' }));
Assert.AreEqual('c', Kata.AddLetters(new char[] { 'a', 'b' }));
Assert.AreEqual('c', Kata.AddLetters(new char[] { 'c' }));
Assert.AreEqual('a', Kata.AddLetters(new char[] { 'z', 'a' }));
Assert.AreEqual('d', Kata.AddLetters(new char[] { 'y', 'c', 'b' }));
Assert.AreEqual('z', Kata.AddLetters(new char[] {}));
}