### Question:
SimpleSelector extends AbstractSelector { public void registerCandidate(Class<?> candidateType, Object candidate) { Set existed = this.candidatesByType.get(candidateType); if (existed == null) { existed = new HashSet(); candidatesByType.put(candidateType, existed); } existed.add(candidate); } SimpleSelector();  SimpleSelector(Class<? extends SelectPolicy> defaultSelectPolicyClass); @SuppressWarnings("unchecked") void registerCandidates(Class<?> candidateType, Set candidates); void registerCandidate(Class<?> candidateType, Object candidate);  }### Answer:
@Test public void test_alias_prop() { Map<String, String> request = new HashMap<>(); request.put("platform", "android"); SimpleSelector selector = new SimpleSelector(); selector.registerCandidate(Handler.class, new WithAliasPropHandler()); Handler handler = selector.select(request, Handler.class); assertThat(handler).isInstanceOf(WithAliasPropHandler.class); }