def perform_count(self, candidate_ids, votes_as_json, max_grade=4):
"""
votes_as_json is a list of tuples, each one being an individual users votes.
And each vote is a tuple with a numeric grade for each candidate, in the natural
order of the candidates.
"""
aggregator = VoteAggregator(candidate_ids, max_grade + 1)
aggregated_votes = aggregator.aggregate(votes_as_json)
scheme = MajorityJudgementCount()
succeeded, result = scheme.sort_candidates(aggregated_votes)
return (
succeeded,
{ x[0]: self._candidate_dict(x[1], n) for n, x in enumerate(result) },
(result[0][0],)
)
def test_complex_tie_breaker(self):
rioja = ('Rioja', (2, 2, 6, 1, 2)) #PPAAGGGGGGVEE, PPEE
bordeaux = ('Bordeaux', (2, 2, 6, 2, 1)) #PPAAGGGGGGVVE, PPVE
tempranillo = ('Tempranillo', (1, 3, 6, 2, 1)) #PAAAGGGGGGVVE, PAVE
input_data = (rioja, bordeaux, tempranillo)
expected = (tempranillo, rioja, bordeaux)
success, actual_output = MajorityJudgementCount().sort_candidates(
input_data)
self.assertEqual(expected, actual_output)
self.assertTrue(success)
def test_simple_tie_breaker(self):
pizza = ('Pizza', (2, 2, 1)) #PPAAG, PPAG, PAG
burger = ('Burger', (0, 3, 2)) #AAAGG, AAGG, AGG
veggie = ('Veggie', (2, 1, 2)) #PPAGG, PPGG, PGG
input_data = (pizza, burger, veggie)
expected_output = (burger, veggie, pizza)
success, actual_output = MajorityJudgementCount().sort_candidates(
input_data)
self.assertEqual(expected_output, actual_output)
self.assertTrue(success)
def test_two_identical_losers(self):
castle = ('Castle', (2, 2, 1)) #PPAAG
fort = ('Fort', (0, 0, 5)) #GGGGG
country_house = ('Country house', (2, 2, 1)) #PPAAG
input_data = (castle, fort, country_house)
expected_output = (fort, castle, country_house)
actual_output = MajorityJudgementCount().sort_candidates(input_data)
self.fail(
"TODO: Sort this test and implementation out - we need to do something better when there are two losers"
)
def test_basic_small_case(self):
pizza = ('Pizza', (1, 1, 3))
burger = ('Burger', (3, 0, 2))
veggie = ('Veggie', (2, 2, 1))
input_data = (pizza, burger, veggie)
expected_output = (pizza, veggie, burger)
success, actual_output = MajorityJudgementCount().sort_candidates(
input_data)
self.assertEqual(expected_output, actual_output)
self.assertTrue(success)
def test_basic_larger_case(self):
chinese = ('Chinese', (12, 40, 6, 8, 7, 26))
pizza = ('Pizza', (2, 10, 21, 4, 17, 45))
indian = ('Indian', (10, 4, 33, 33, 2, 17))
burger = ('Burger', (6, 12, 40, 26, 7, 8))
input_data = (chinese, pizza, indian, burger)
expected_output = (pizza, indian, burger, chinese)
success, actual_output = MajorityJudgementCount().sort_candidates(
input_data)
self.assertEqual(expected_output, actual_output)
self.assertTrue(success)
def test_incomplete_vote(self):
"""
We are expecting the input data to have votes for each of the candidates
(i.e. any padding with 0 or defaulting to 'reject' should happen before
it gets to us. If the data is not complete in this way, we raise an
IncompleteVoteError.
"""
pizza = ('Pizza', (3, 1, 1))
burger = ('Burger', (2, 0))
veggie = ('Veggie', (1, 2, 2))
input_data = (pizza, burger, veggie)
with self.assertRaises(IncompleteVoteError):
MajorityJudgementCount().sort_candidates(input_data)
def test_two_identical_winners(self):
"""
When the two highest ranked candidates have identical vote
distributions we cannot pick a winner and an exception should be
raised.
"""
smith = ('L. Smith', (2, 7, 5, 8, 3))
jones = ('Q. Jones', (11, 9, 2, 3, 0))
rogers = ('P. Rogers', (2, 7, 5, 8, 3))
input_data = (smith, jones, rogers)
success, actual_output = MajorityJudgementCount().sort_candidates(
input_data)
self.assertIn(actual_output[0], [smith, rogers])
self.assertIn(actual_output[1], [smith, rogers])
self.assertEqual(actual_output[2], jones)
self.assertFalse(success)
def test_even_number_of_voters_different_medians(self):
"""
In this case, there are 6 voters.
If we used the 4th item for the median, result order would be red, blue, green.
But, if we use the 3th item for the median, result would be blue, red, green.
The second is the *correct* way.
"""
red = ('Red party', (3, 0, 3)) #PPPGGG
blue = ('Blue party', (2, 2, 2)) #PPAAGG
green = ('Green party', (4, 0, 2)) #PPPPGG
input_data = (red, blue, green)
expected_output = (blue, red, green)
success, actual_output = MajorityJudgementCount().sort_candidates(
input_data)
self.assertEqual(expected_output, actual_output)
self.assertTrue(success)