assertFalse(CharSource.concat(c1, c2, c3).isEmpty());

    CharSource emptyConcat = CharSource.concat(CharSource.empty(), CharSource.empty());
    assertTrue(emptyConcat.isEmpty());
  }

  public void testConcat_infiniteIterable() throws IOException {
    CharSource source = CharSource.wrap("abcd");
    Iterable<CharSource> cycle = Iterables.cycle(ImmutableList.of(source));
    CharSource concatenated = CharSource.concat(cycle);