@Test
public void testConcat() {

    assertEquals(Arrays.asList(1, 2, 3), Iterables
            .toList(Iterables.concat(Arrays.asList(1, 2, 3), Arrays.asList())));
    assertEquals(Arrays.asList(1, 2, 3), Iterables
            .toList(Iterables.concat(Arrays.asList(), Arrays.asList(1, 2, 3))));
    assertEquals(Arrays.asList(), Iterables.toList(Iterables.concat(Arrays.asList(), Arrays.asList())));
    assertEquals(Arrays.asList(1, 2, 3, 4, 5, 6), Iterables.toList(Iterables.concat(Arrays.asList(1, 2, 3), Arrays
            .asList(4, 5, 6))));
}