@Test
public void testNextString() {

    // zaleznosci
    ValueHolder h1 = new StringHolder("a");
    ValueHolder h2 = new NumberHolder(BigDecimal.ONE);
    ValueHolder h3 = new IntegerHolder(9L);
    // testowany obiekt
    MultiValue mv = new DefaultMultiValue(new Object[]{h1, h2, h3});
    // oczekiwane wartosci
    assertEquals("a", mv.nextString());
    assertEquals("1", mv.nextString());
    assertEquals("9", mv.nextString());
}