def test_list_donors():
    dl = Donorlist(init_tuple)
    assert type(dl.list_donors()) == list
    assert dl.list_donors() == [
        'Burt Reynolds', 'John Waters', 'Nick Offerman', 'Sam Elliot',
        'Tom Selleck'
    ]
def test_add_donor():
    dl = Donorlist(init_tuple)
    dl.add_donor('Gene Shallit')
    assert 'Gene Shallit' in dl.list_donors()
    assert isinstance(dl.get_donor('Gene Shallit'), Donor)
    assert dl.list_donations('Gene Shallit') == []
    with pytest.raises(ValueError):
        dl.add_donor('Tom Selleck')