### Question:
SlackClient implements AutoCloseable { public Response message(String channelId, String ts, boolean replyBroadcast, String text, String iconEmoji, String username, Collection<Object> attachments) throws IOException { Map<String, Object> params = new HashMap<>(); params.put("channel", channelId); params.put("as_user", true); params.put("text", text); if (ts != null) { params.put("thread_ts", ts); params.put("reply_broadcast", replyBroadcast); } if (iconEmoji != null) { params.put("icon_emoji", iconEmoji); params.put("as_user", false); } if (username != null) { params.put("username", username); params.put("as_user", false); } if (attachments != null) { params.put("attachments", attachments); } return exec(CHAT_POST_MESSAGE_CMD, params); } SlackClient(SlackConfiguration cfg); @Override void close(); Response addReaction(String channelId, String ts, String reaction); Response postJsonMessage(String json); Response updateJsonMessage(String json); Response message(String channelId, String ts, boolean replyBroadcast, String text, String iconEmoji, String username, Collection<Object> attachments); Response createChannel(String channelName); Response createGroupChannel(String channelName); Response archiveChannel(String channelId); Response archiveGroup(String channelId);  }### Answer:
@Test public void validateSlackClientPostingMessageWithParameters() throws Exception { Map<String, Object> cfgMap = new HashMap<>(); cfgMap.put("apiToken", TestParams.TEST_API_TOKEN); SlackClient client = new SlackClient(SlackConfiguration.from(new SlackConfigurationParams(new MapBackedVariables(cfgMap)))); String channelId = TestParams.TEST_CHANNEL; SlackClient.Response response = client.message(channelId, null, false, "Hello from Concord!", null, null, null); assertTrue(response.isOk()); }