@Test
public void testAddToValue() {

    array5Vector.addToValue(2, 5.0);
    assertEquals(5, array5Vector.getArrayRef()[2], 0.0); // should be exactly the same, so delta=0.0
    // test automatic vector enlargement
    emptyVector.addToValue(0, 1.0);
    assertEquals(1, emptyVector.getArrayRef()[0], 0.0); // should be exactly the same, so delta=0.0
}