@Test
public void testHorizontalSum() {

    CrossTable sum = CrossTable.horizontalSum(table, other);
    
    assertEquals(sum.getNumberOfRows(), 6);
    assertEquals(sum.getNumberOfColumns(), 6);
    assertEquals(sum.getRow(0).intent, bits(1, 2));
    assertEquals(sum.getRow(3).intent, bits(4, 5));
    assertEquals(sum.getRow(5).intent, bits());
}