HashAttributeSet testSet2 = new HashAttributeSet();
testSet2.add(att2);
testSet2.add(att3);
harness.check(testSet.equals(testSet2), true, "equals");
harness.check(testSet2.addAll(testSet), false, "addAll");
testSet2.clear();
harness.check(testSet2.isEmpty(), true, "isEmpty");
// test hashcode
testSet = new HashAttributeSet();