### Question:
RedisDataStore implements DataStore { @Override public void removeChannels(final Set<String> channelIds) { for (String channelId : channelIds) { removeChannel(channelId); } } RedisDataStore(final String host, final int port); @Override void savePrivateKeySalt(final byte[] salt); @Override byte[] getPrivateKeySalt(); @Override boolean saveChannel(final Channel channel); @Override void removeChannels(final Set<String> channelIds); @Override Channel getChannel(final String channelId); @Override Set<String> getChannelIds(final String uaid); @Override void removeChannels(final String uaid); @Override String updateVersion(final String endpointToken, final long newVersion); @Override String saveUnacknowledged(final String channelId, final long version); @Override Set<Ack> getUnacknowledged(final String uaid); @Override Set<Ack> removeAcknowledged(final String uaid, final Set<Ack> acks);  }### Answer:
@Test public void removeChannels() throws ChannelNotFoundException { final RedisDataStore store = newRedisDataStore(); final String uaid = UUIDUtil.newUAID(); final Channel ch1 = newChannel2(uaid); final Channel ch2 = newChannel2(uaid); store.saveChannel(ch1); store.saveChannel(ch2); store.removeChannels(new HashSet<String>(Arrays.asList(ch1.getChannelId(), ch2.getChannelId()))); assertThat(store.getChannelIds(uaid).size(), is(0)); }