assertEquals("a, b, c", set("a", "b", "c"));
assertEquals("a, b, c", set("c", "b", "a"));
}
private String set(String... args) {
Set<String> items = new TreeSet<>(new StringLengthComparator());
items.addAll(Arrays.asList(args));
return Joiner.on(", ").join(items);
}