@Test
 public void testIterator() {
   subject = new AttributeCollection(dataset, 0);
   int i = 0;
   Iterator it = subject.iterator();
   while (it.hasNext()) {
     assertNotNull(it.next());
     i++;
   }
   assertEquals(2, i);
 }
 @Test
 public void testIsEmpty() {
   subject = new AttributeCollection(dataset, 3);
   assertEquals(false, subject.isEmpty());
 }
 @Test
 public void testContains() {
   subject = new AttributeCollection(dataset, 0);
   assertEquals(true, subject.contains(1.0));
   assertEquals(true, subject.contains(6.0));
 }
  @Test
  public void testSize() {
    subject = new AttributeCollection(dataset, 0);

    assertEquals(2, subject.size());
  }