'Regression test for #13902: When using a ManyToMany in list_filter,
results shouldn\'t apper more than once. With an intermediate model.'

def test_distinct_for_through_m2m_in_list_filter(self):

    lead = Musician.objects.create(name='Vox')
    band = Group.objects.create(name='The    Hype')
    Membership.objects.create(group=band, music=lead, role='lead    voice')
    Membership.objects.create(group=band, music=lead, role='bass    player')
    m = GroupAdmin(Group, admin.site)
    cl = ChangeList(MockFilteredRequestB(lead.pk), Group, 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)
