@Test
  public void testAddOnUserListListener() throws Exception {
    CompletableFuture<String> channelNameFuture = new CompletableFuture<>();
    CompletableFuture<Map<String, ChatUser>> usersFuture = new CompletableFuture<>();
    instance.addOnUserListListener(
        (channelName, users) -> {
          channelNameFuture.complete(channelName);
          usersFuture.complete(users);
        });
    when(chatPrefs.getChatColorMode()).thenReturn(chatColorMode.get());
    when(chatPrefs.getUserToColor()).thenReturn(userToColorProperty);

    when(user2.compareTo(user1)).thenReturn(1);
    ImmutableSortedSet<User> users = ImmutableSortedSet.of(user1, user2);
    instance.onEvent(new UserListEvent(pircBotX, defaultChannel, users, true));

    assertThat(channelNameFuture.get(TIMEOUT, TIMEOUT_UNIT), is(DEFAULT_CHANNEL_NAME));

    Map<String, ChatUser> userMap = usersFuture.get(TIMEOUT, TIMEOUT_UNIT);
    assertThat(userMap.values(), hasSize(2));
    assertThat(userMap.get(chatUser1.getUsername()), is(chatUser1));
    assertThat(userMap.get(chatUser2.getUsername()), is(chatUser2));
  }