Add test case for ERS97 BLT with Meek STV

tests/data/ers97_meekm.csv

@@ -0,0 +1,15 @@
+Stage:,1,,2,,4,,6,,9,,11,
+Comment:,First preferences,,Surpluses distributed,,Surpluses distributed,,Surpluses distributed,,Surpluses distributed,,Surpluses distributed,
+Smith,134,EL,107.26,EL,106.96,EL,104.42,EL,101.58,EL,73,EL
+Carpenter,81,,87.98,,88.47,,97.71,,101.58,EL,73,EL
+Wright,27,,31.99,,32.34,,34.97,,0,EX,0,EX
+Glazier,24,,30.19,,30.62,,0,EX,0,EX,0,EX
+Duke,105,,106.6,,106.96,EL,104.42,EL,101.58,EL,73,EL
+Prince,91,,91,,91,,92.45,,97.07,,73,EL
+Baron,64,,64,,64,,64.03,,67.24,,0,EX
+Abbot,59,,59.8,,64.85,,66,,68.92,,70.83,
+Vicar,55,,55,,69.21,,70.99,,73.27,,75.16,EL
+Monk,23,,23.4,,0,EX,0,EX,0,EX,0,EX
+Freeman,90,,93.59,,94.27,,95.97,,99.81,,73,EL
+Exhausted,0,,2.2,,4.31,,22.05,,41.95,,242.01,
+Quota,107.57,,107.26,,106.96,,104.42,,101.58,,73.01,

tests/test_ers97.py

@@ -19,7 +19,7 @@ from pytest_steps import test_steps
 import pyRCV2.blt
 import pyRCV2.numbers
 from pyRCV2.method.gregory import EGSTVCounter
-from pyRCV2.model import CandidateState, CountCompleted
+from pyRCV2.model import CandidateState
 import tests.util
 
 import csv

tests/test_ers97_meekm.py

@@ -0,0 +1,85 @@
+#   pyRCV2: Preferential vote counting
+#   Copyright © 2020–2021  Lee Yingtong Li (RunasSudo)
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU Affero General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU Affero General Public License for more details.
+#
+#   You should have received a copy of the GNU Affero General Public License
+#   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+from pytest_steps import test_steps
+
+import pyRCV2.blt
+import pyRCV2.numbers
+from pyRCV2.method.meek import MeekSTVCounter
+from pyRCV2.model import CandidateState
+import tests.util
+
+import csv
+
+def isclose(a, b):
+	# Allow discrepancy of ~0.01
+	diff = a - b
+	if diff < pyRCV2.numbers.Num('0.014') and diff > pyRCV2.numbers.Num('-0.014'):
+		return True
+	return False
+
+# Read model CSV
+
+with open('tests/data/ers97_meekm.csv', 'r', newline='') as f:
+	reader = csv.reader(f)
+	data = [x for x in reader]
+
+candidates = [data[i][0] for i in range(2, len(data) - 2)]
+
+@test_steps(*['Stage {}'.format(data[0][i]) for i in range(1, len(data[0]), 2)])
+def test_ers97_meekm_py():
+	"""Compare count of ers97.blt with model result produced by Hill et al. reference implementation"""
+	
+	pyRCV2.numbers.set_numclass(pyRCV2.numbers.FixedGuarded)
+	pyRCV2.numbers.set_dps(4)
+	
+	with open('tests/data/ers97.blt', 'r') as f:
+		election = pyRCV2.blt.readBLT(f.read())
+	
+	assert len(election.candidates) == len(candidates)
+	
+	counter = MeekSTVCounter(election, {
+		'quota': 'droop_exact',
+		'quota_criterion': 'gt',
+		'quota_mode': 'progressive',
+		'ties': []
+	})
+	result = counter.reset()
+	
+	for i in range(1, len(data[0]), 2):
+		stage = int(data[0][i])
+		
+		while len(counter.step_results) < stage:
+			result = counter.step()
+		
+		comment = data[1][i]
+		assert result.comment == comment, 'Failed to verify comment'
+		
+		for j, cand in enumerate(candidates):
+			votes = pyRCV2.numbers.Num(data[j + 2][i])
+			cc = next(cc for c, cc in result.candidates.items() if c.name == cand)
+			assert isclose(cc.votes, votes), 'Failed to verify candidate "{}" votes, got {} expected {}'.format(cand, cc.votes.pp(2), votes.pp(2))
+			
+			state = data[j + 2][i + 1] if len(data[j + 2]) > (i + 1) else ''
+			accept = {'': CandidateState.HOPEFUL, 'EL': CandidateState.ELECTED, 'EX': CandidateState.EXCLUDED}
+			assert cc.state == accept[state], 'Failed to verify candidate "{}" state'.format(cand)
+		
+		# NB: Ignore exhausted votes
+		
+		quota = pyRCV2.numbers.Num(data[len(candidates) + 3][i])
+		assert isclose(result.quota, quota), 'Failed to verify quota, got {} expected {}'.format(result.quota.pp(2), quota.pp(2))
+		
+		yield 'Stage {}'.format(stage)

tests/test_meekm.py

@@ -23,7 +23,7 @@ from pyRCV2.method.meek import MeekSTVCounter
 from pyRCV2.model import CandidateState, CountCompleted
 from pyRCV2.ties import TiesBackwards
 
-def test_meekm():
+def test_meekm_py():
 	"""Compare count of meekm.blt with model result produced by Hill et al. reference implementation"""
 	
 	pyRCV2.numbers.set_numclass(pyRCV2.numbers.FixedGuarded)