assertEquals(1, mergedItems.length);
        // Total frequency should be 1+2+3+4+5 = 15
        assertEquals(15, mergedItems[0].getDocFreq());
    }

    @Test
    public void test_mergeItemsWithNoMatch() throws Exception {
        String[][] readings1 = new String[1][];
        readings1[0] = new String[] { "test1" };
        String[][] readings2 = new String[1][];
        readings2[0] = new String[] { "test2" };