@Test
public void testDense() throws Exception {

  ARFFModel model = new MapBackedARFFModel();
  Iterable<Vector> iterable = new ARFFVectorIterable(SAMPLE_DENSE_ARFF, model);
  Vector firstVector = iterable.iterator().next();
  assertEquals(1.0, firstVector.get(0), 0);
  assertEquals(65.0, firstVector.get(1), 0);
  assertEquals(1.0, firstVector.get(3), 0);
  assertEquals(1.0, firstVector.get(4), 0);
  
  int count = 0;
  for (Vector vector : iterable) {
    assertTrue("Vector is not dense", vector instanceof DenseVector);
    count++;
  }
  assertEquals(5, count);
}