public void GetSmallestPositiveDurationWithNegative()
    {
        var durations = new Durations(2, -1);

        Assert.AreEqual(2, durations.GetSmallestPositiveDuration());
    }
    public void GetSmallestPositiveDurationException()
    {
        var durations = new Durations(-2, -1);

        Assert.ThrowsException <NegativeValueException>(() => durations.GetSmallestPositiveDuration());
    }
    public void GetSmallestPositiveDuration()
    {
        var durations = new Durations(2, 1);

        Assert.AreEqual(1, durations.GetSmallestPositiveDuration());
    }