### Question:
CollectionUtil { public static boolean contains(final Collection<?> collection, final Object item) { return collection != null && collection.contains(item); } private  CollectionUtil(); static boolean isEmpty(final Collection<?> col); static boolean isNotEmpty(final Collection<?> col); static boolean hasOneItem(final Collection<?> col); static boolean isNotEmpty(final Object[] array); static int size(final Collection<?> col); static boolean contains(final Collection<?> collection, final Object item); static boolean containsAny(final Collection<?> collection, final Object... items); static boolean noneEmpty(final Collection<?>... collections); static boolean sameContent(final Collection<?> c1, final Collection<?> c2);  }### Answer:
@Test public void testContains() { assertFalse("null", CollectionUtil.contains((Collection<?>) null, "bla")); final HashSet<Object> col = new HashSet<>(); assertFalse("empty", CollectionUtil.contains(col, "bla")); col.add(1); assertFalse("1", CollectionUtil.contains(col, "bla")); col.add("bla"); assertTrue("1 + bla", CollectionUtil.contains(col, "bla")); }