code: public void assertContains(Description description, Set<?> actual, Object[] values) {
      assertNotNull(description, actual);
      checkNotEmpty(description, actual);
      checkIsNotNullAndNotEmpty(values);
      Set<Object> notFound = new LinkedHashSet<Object>();
      for (Object value : values) {
        if (!actual.contains(value)) {
          notFound.add(value);
        }
      }
      if (!notFound.isEmpty()) {
        throw failures.failure(description, ShouldContain.shouldContain(actual, values, notFound));
      }
    }
docs: Asserts that the given {@code Set} contains the given object.
  
  @param description contains information about the assertion.
  @param actual the given {@code Set}.
  @param values the object to look for.
  @throws AssertionError if the given {@code Set} is {@code null} or empty.
  @throws AssertionError if the given {@code Set} does not contain the given object.