'Regression test for #13902: When using a ManyToMany in list_filter,
results shouldn\'t apper more than once. Target of the relationship
inherits from another.'

def test_distinct_for_m2m_to_inherited_in_list_filter(self):

    lead = ChordsMusician.objects.create(name='Player    A')
    three = ChordsBand.objects.create(name='The    Chords    Trio')
    Invitation.objects.create(band=three, player=lead, instrument='guitar')
    Invitation.objects.create(band=three, player=lead, instrument='bass')
    m = ChordsBandAdmin(ChordsBand, admin.site)
    cl = ChangeList(MockFilteredRequestB(lead.pk), ChordsBand, m.list_display, m.list_display_links, m.list_filter, m.date_hierarchy, m.search_fields, m.list_select_related, m.list_per_page, m.list_editable, m)
    cl.get_results(MockFilteredRequestB(lead.pk))
    self.assertEqual(cl.result_count, 1)
