public void SetTest()
{
var a = new IntSet();
a.Add(1);
a.Add(3, 6);
a.Add(2);
var b = new IntSet();
b.Add(1, 6);
Assert.AreEqual(b, a);
a.Add(-2, -1);
a.Add(0, 1);
var c = new IntSet();
c.Add(0, 6);
c.Add(-2);
Assert.AreEqual(c, a);
a.Add(-1, 9);
var d = new IntSet();
d.Add(-2, 9);
Assert.AreEqual(d, a);
Assert.AreEqual(-3, c.LowestFree(-3));
Assert.AreEqual(-1, c.LowestFree(-2));
Assert.AreEqual(-1, c.LowestFree(-1));
Assert.AreEqual(6, c.LowestFree(0));
Assert.AreEqual(6, c.LowestFree(5));
Assert.AreEqual(12, c.LowestFree(12));
}