@Test
public void testCloseClosesUnderlyingStreams() throws Exception {

    InputStream a = mock(InputStream.class);
    InputStream b = mock(InputStream.class);
    InputStream c = mock(InputStream.class);
    ImmutableList<InputStream> inputStreams = ImmutableList.of(a, b, c);
    ConcatClosingInputStream concatClosingInputStream = new ConcatClosingInputStream(inputStreams.iterator());
    concatClosingInputStream.close();
    verify(a).close();
    verify(b).close();
    verify(c).close();
}