@Test
public void testGetSimilarities_RoomByEmoji() throws Exception {

    DateTimeFormatter dtf = DateTimeUtils.PARAMETER_WITH_DAY_DTF.withZone(dtZone);
    String startTimeStr = dtf.print(mentionTime.minusDays(1));
    String endTimeStr = dtf.print(mentionTime.plusDays(1));
    LabeledDenseMatrix<String> ldm = underTest.getSimilarities(
            startTimeStr, endTimeStr, DimensionType.ROOM.getDimensionName(),
            DimensionType.EMOJI.getDimensionName(), null);
    assertEquals(4, ldm.getLabels().size());
    assertEquals(4, ldm.getMatrix().length);
}