def test_tally_spoiled_ballots_accumulates_valid_tally(
self, everything: ELECTIONS_AND_BALLOTS_TUPLE_TYPE):
# Arrange
metadata, ballots, secret_key, context = everything
# Tally the plaintext ballots for comparison later
plaintext_tallies = accumulate_plaintext_ballots(ballots)
# encrypt each ballot
store = BallotStore()
seed_hash = EncryptionDevice("Location").get_hash()
for ballot in ballots:
encrypted_ballot = encrypt_ballot(ballot, metadata, context,
seed_hash)
seed_hash = encrypted_ballot.tracking_hash
self.assertIsNotNone(encrypted_ballot)
# add to the ballot store
store.set(
encrypted_ballot.object_id,
from_ciphertext_ballot(encrypted_ballot,
BallotBoxState.SPOILED),
)
# act
result = tally_ballots(store, metadata, context)
self.assertIsNotNone(result)
# Assert
decrypted_tallies = self._decrypt_with_secret(result, secret_key)
self.assertCountEqual(plaintext_tallies, decrypted_tallies)
for value in decrypted_tallies.values():
self.assertEqual(0, value)
self.assertEqual(len(ballots), len(result.spoiled_ballots))
def _generate_encrypted_tally(
self,
metadata: InternalElectionDescription,
context: CiphertextElectionContext,
ballots: List[PlaintextBallot],
) -> CiphertextTally:
# encrypt each ballot
store = BallotStore()
for ballot in ballots:
encrypted_ballot = encrypt_ballot(ballot, metadata, context,
int_to_q_unchecked(1))
self.assertIsNotNone(encrypted_ballot)
# add to the ballot store
store.set(
encrypted_ballot.object_id,
from_ciphertext_ballot(encrypted_ballot, BallotBoxState.CAST),
)
tally = tally_ballots(store, metadata, context)
self.assertIsNotNone(tally)
return get_optional(tally)
def test_ballot_store(self):
# Arrange
keypair = elgamal_keypair_from_secret(int_to_q(2))
election = election_factory.get_fake_election()
metadata, context = election_factory.get_fake_ciphertext_election(
election, keypair.public_key)
# get an encrypted fake ballot to work with
fake_ballot = election_factory.get_fake_ballot(metadata)
encrypted_ballot = encrypt_ballot(fake_ballot, metadata, context,
SEED_HASH)
# Set up the ballot store
subject = BallotStore()
data_cast = CiphertextAcceptedBallot(
encrypted_ballot.object_id,
encrypted_ballot.ballot_style,
encrypted_ballot.description_hash,
encrypted_ballot.previous_tracking_hash,
encrypted_ballot.contests,
encrypted_ballot.tracking_hash,
encrypted_ballot.timestamp,
)
data_cast.state = BallotBoxState.CAST
data_spoiled = CiphertextAcceptedBallot(
encrypted_ballot.object_id,
encrypted_ballot.ballot_style,
encrypted_ballot.description_hash,
encrypted_ballot.previous_tracking_hash,
encrypted_ballot.contests,
encrypted_ballot.tracking_hash,
encrypted_ballot.timestamp,
)
data_spoiled.state = BallotBoxState.SPOILED
self.assertIsNone(subject.get("cast"))
self.assertIsNone(subject.get("spoiled"))
# try to set a ballot with an unknown state
self.assertFalse(
subject.set(
"unknown",
CiphertextAcceptedBallot(
encrypted_ballot.object_id,
encrypted_ballot.ballot_style,
encrypted_ballot.description_hash,
encrypted_ballot.previous_tracking_hash,
encrypted_ballot.contests,
encrypted_ballot.tracking_hash,
encrypted_ballot.timestamp,
),
))
# Act
self.assertTrue(subject.set("cast", data_cast))
self.assertTrue(subject.set("spoiled", data_spoiled))
self.assertEqual(subject.get("cast"), data_cast)
self.assertEqual(subject.get("spoiled"), data_spoiled)
self.assertEqual(subject.exists("cast"), (True, data_cast))
self.assertEqual(subject.exists("spoiled"), (True, data_spoiled))
# test mutate state
data_cast.state = BallotBoxState.UNKNOWN
self.assertEqual(subject.exists("cast"), (False, data_cast))
# test remove
self.assertTrue(subject.set("cast", None))
self.assertEqual(subject.exists("cast"), (False, None))
def test_tally_ballot_invalid_input_fails(
self, everything: ELECTIONS_AND_BALLOTS_TUPLE_TYPE):
# Arrange
metadata, ballots, secret_key, context = everything
# encrypt each ballot
store = BallotStore()
seed_hash = EncryptionDevice("Location").get_hash()
for ballot in ballots:
encrypted_ballot = encrypt_ballot(ballot, metadata, context,
seed_hash)
seed_hash = encrypted_ballot.tracking_hash
self.assertIsNotNone(encrypted_ballot)
# add to the ballot store
store.set(
encrypted_ballot.object_id,
from_ciphertext_ballot(encrypted_ballot, BallotBoxState.CAST),
)
subject = CiphertextTally("my-tally", metadata, context)
# act
cached_ballots = store.all()
first_ballot = cached_ballots[0]
first_ballot.state = BallotBoxState.UNKNOWN
# verify an UNKNOWN state ballot fails
self.assertIsNone(tally_ballot(first_ballot, subject))
self.assertFalse(subject.append(first_ballot))
# cast a ballot
first_ballot.state = BallotBoxState.CAST
self.assertTrue(subject.append(first_ballot))
# try to append a spoiled ballot
first_ballot.state = BallotBoxState.SPOILED
self.assertFalse(subject.append(first_ballot))
# Verify accumulation fails if the selection collection is empty
if first_ballot.state == BallotBoxState.CAST:
self.assertFalse(
subject.cast[first_ballot.object_id].elgamal_accumulate([]))
# pop the cast ballot
subject._cast_ballot_ids.pop()
# reset to cast
first_ballot.state = BallotBoxState.CAST
self.assertTrue(
self._cannot_erroneously_mutate_state(subject, first_ballot,
BallotBoxState.CAST))
self.assertTrue(
self._cannot_erroneously_mutate_state(subject, first_ballot,
BallotBoxState.SPOILED))
self.assertTrue(
self._cannot_erroneously_mutate_state(subject, first_ballot,
BallotBoxState.UNKNOWN))
# verify a spoiled ballot cannot be added twice
first_ballot.state = BallotBoxState.SPOILED
self.assertTrue(subject.append(first_ballot))
self.assertFalse(subject.append(first_ballot))
# verify an already spoiled ballot cannot be cast
first_ballot.state = BallotBoxState.CAST
self.assertFalse(subject.append(first_ballot))
# pop the spoiled ballot
subject.spoiled_ballots.pop(first_ballot.object_id)
# verify a cast ballot cannot be added twice
first_ballot.state = BallotBoxState.CAST
self.assertTrue(subject.append(first_ballot))
self.assertFalse(subject.append(first_ballot))
# verify an already cast ballot cannot be spoiled
first_ballot.state = BallotBoxState.SPOILED
self.assertFalse(subject.append(first_ballot))