public void TestIntersect()
{
HashCollection <int> a = new HashCollection <int> {
1, 2
};
HashCollection <int> b = new HashCollection <int> {
2, 3
};
ISet c = a.Intersect(b);
Assert.IsNotNull(c);
Assert.IsFalse(c.Contains(1));
Assert.IsTrue(c.Contains(2));
Assert.IsFalse(c.Contains(3));
Assert.IsFalse(c.Contains(4));
}