@Test
public void splitAfterTest() {

    int[][] cellData = new int[][]{{0, 1}, {2, 3, 4}, {5, 6}};
    Partition p = new Partition(cellData);
    int cellIndex = 1;
    int splitElement = 3;
    Partition q = p.splitAfter(cellIndex, splitElement);
    Assert.assertEquals(p.numberOfElements(), q.numberOfElements());
    Assert.assertEquals(p.size() + 1, q.size());
    SortedSet<Integer> cell = q.getCell(cellIndex + 1);
    Assert.assertTrue(cell.size() == 1);
    Assert.assertEquals(splitElement, (int) cell.first());
}