public void TestIntersectWith() { var testSet = new ThreadSafeSet <string>(new HashSet <string>()); var bSet = new[] { "b" }; testSet.Add("a"); testSet.Add("b"); testSet.IntersectWith(bSet); Assert.AreEqual("b", testSet.Single()); testSet.IntersectWith(bSet); Assert.AreEqual("b", testSet.Single()); }