@Test
public void testNullGroups() {

    dataSetLookup = new DataSetLookup();
    String userId = "userId";
    when(userGroupCallback.getGroupsForUser(userId)).thenReturn(null);
    when(identityProvider.getName()).thenReturn(userId);
    preprocessor.preprocess(dataSetLookup);
    assertEquals("ID = userId",
                 dataSetLookup.getFirstFilterOp().getColumnFilterList().get(0).toString());
}