public void NeededDiamonds()
{
Calculator calculator = new Calculator();
Assert.AreEqual(1, calculator.NeededDiamonds(0));
Assert.AreEqual(1 + 5, calculator.NeededDiamonds(1));
Assert.AreEqual(1 + 5 + 9, calculator.NeededDiamonds(2));
Assert.AreEqual(1 + 5 + 9 + 13, calculator.NeededDiamonds(3));
}
