### Question:
CollectionUtils { @SafeVarargs public static <T> Set<T> setOf(T... t) { return new LinkedHashSet<>(asList(t)); }  static T singleValue(Collection<T> values); static List<T> join(Collection<T> first, Collection<T> second); static List<T> minus(Collection<T> first, Collection<T> second); static Set<T> joinToSet(Collection<T> first, Collection<T> second); @SafeVarargs static Set<T> setOf(T... t);  }### Answer:
@Test void testSetOf() { assertEquals(new LinkedHashSet<>(asList(3, 1, 2)), setOf(3, 1, 2, 3, 1, 2)); }