static void verifyInterestRegistration() {
    await("Number of cache servers (" + cache.getCacheServers().size() + ") never became 1")
        .until(() -> cache.getCacheServers().size(), equalTo(1));

    CacheServerImpl bs = (CacheServerImpl) cache.getCacheServers().iterator().next();
    assertThat(bs).isNotNull();
    assertThat(bs.getAcceptor()).isNotNull();
    assertThat(bs.getAcceptor().getCacheClientNotifier()).isNotNull();

    final CacheClientNotifier ccn = bs.getAcceptor().getCacheClientNotifier();
    await("Notifier's proxies is empty")
        .until(() -> ccn.getClientProxies().size(), greaterThan(0));

    Iterator<CacheClientProxy> cacheClientProxyIterator = ccn.getClientProxies().iterator();

    assertThat(cacheClientProxyIterator.hasNext()).describedAs("A CCP was expected . Wasn't it?")
        .isTrue();
    final CacheClientProxy ccp = cacheClientProxyIterator.next();

    await().until(() -> {
      Set keysMap = ccp.cils[RegisterInterestTracker.interestListIndex]
          .getProfile(SEPARATOR + REGION_NAME).getKeysOfInterestFor(ccp.getProxyID());
      if (keysMap == null) {
        return false;
      }
      return keysMap.size() == 2;
    });

    Set keysMap = ccp.cils[RegisterInterestTracker.interestListIndex]
        .getProfile(SEPARATOR + REGION_NAME).getKeysOfInterestFor(ccp.getProxyID());
    assertThat(keysMap.contains(k1)).isTrue();
    assertThat(keysMap.contains(k2)).isTrue();
  }
@param connectedServers is the expected number of connected servers (1 or more)
@param redundantServers is the expected number of redundant servers (0 or more)
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/RedundancyLevelTestBase.java