def test_add_donation():
donors = Donors()
donors.add_donation("Mark", 10)
assert donors.get_donor("Mark") == Donor("Mark", 10)
donors.add_donation("Mark", 20)
assert donors.get_donor("Mark").donations == (10, 20)
donors.add_donation("Mary", 30)
assert donors.get_donor("Mary") == Donor("Mary", 30)
assert set(donors.names) == set(["Mark", "Mary"])
def test_get_donor():
donors = Donors()
d = Donor("Mark", 50)
donors.add_donor(d)
assert donors.get_donor("Mark") == d
assert donors.get_donor("Mary") is None