@Test
public void testPotOwnerFilterWithEmptyPotOwnerList() {

    String userId = "userId";
    when(userGroupCallback.getGroupsForUser(userId)).thenReturn(null);
    when(identityProvider.getName()).thenReturn(userId);
    List<String> potOwners = new ArrayList<String>();
    QueryParam queryParam = new QueryParam(COL_ID, "IN", potOwners);
    List<QueryParam> queryParams = new ArrayList<QueryParam>();
    queryParams.add(queryParam);
    CoreFunctionQueryParamBuilder coreFunctionQueryParamBuilder = new CoreFunctionQueryParamBuilder(queryParam);
    CoreFunctionFilter columnFilter = (CoreFunctionFilter) coreFunctionQueryParamBuilder.build();
    DataSetFilter filter = new DataSetFilter();
    filter.addFilterColumn(columnFilter);
    dataSetLookup.addOperation(filter);
    userAndGroupsTasksPreprocessor.preprocess(dataSetLookup);
    assertEquals("(POTOWNER in " + userId + ")",
                 dataSetLookup.getFirstFilterOp().getColumnFilterList().get(0).toString());
}