### Question:
Rules implements Iterable<Rule> { public void clear() { rules.clear(); } Rules(Set<Rule> rules);  Rules(Rule... rules);  Rules(Object... rules); void register(Object... rules); void unregister(Object... rules); void unregister(final String ruleName); boolean isEmpty(); void clear(); int size(); @Override Iterator<Rule> iterator();  }### Answer:
@Test public void clear() { rules.register(new DummyRule()); rules.clear(); assertThat(rules).isEmpty(); }