@Test
public void testGetCategoryCombos()
{

    CategoryCombo ccA = new CategoryCombo( "CategoryComboA", DataDimensionType.DISAGGREGATION );
    CategoryCombo ccB = new CategoryCombo( "CategoryComboB", DataDimensionType.DISAGGREGATION );
    DataSet dsA = new DataSet( "DataSetA" );
    DataSet dsB = new DataSet( "DataSetB" );
    DataElement deA = new DataElement( "DataElementA" );
    DataElement deB = new DataElement( "DataElementB" );
    deA.setCategoryCombo( ccA );
    dsA.addDataSetElement( deA );
    dsB.addDataSetElement( deA, ccB );
    assertEquals( 2, deA.getCategoryCombos().size() );
    assertEquals( Sets.newHashSet( ccA, ccB ), deA.getCategoryCombos() );
    deB.setCategoryCombo( ccA );
    dsB.addDataSetElement( deB );
    assertEquals( 1, deB.getCategoryCombos().size() );
    assertEquals( Sets.newHashSet( ccA ), deB.getCategoryCombos() );
}