public void TestIsProperSubsetOf()
{
var testSet = new ThreadSafeSet <string>(new HashSet <string>());
var bSet = new[] { "a", "b", "c" };
var dSet = new[] { "b", "c", "d" };
testSet.Add("a");
testSet.Add("b");
Assert.IsTrue(testSet.IsProperSubsetOf(bSet));
Assert.IsFalse(testSet.IsProperSubsetOf(dSet));
}