public void N_4_K_1_Expected_4()
{
int[] data = { 2, 3, 6, 1 };
int n = data.Length;
int k = 1;
Combinations combinations = new Combinations();
List<List<int>> combination = combinations.Generate(data, 0, k);
Assert.That(combination.Count, Is.EqualTo(Fact(n) / (Fact(k) * Fact(n - k))));
Assert.That(combination[0], Is.EqualTo(new List<int>{2}));
Assert.That(combination[3], Is.EqualTo(new List<int>{1}));
}