class TestExtensionCalculation(TestCase):
def setUp(self):
self.assumptions = {'alpha', 'beta', 'gamma', 'delta'}
self.language = self.assumptions.union({'phi', 'psi', 'chi'})
self.assumptions_to_contrary_mapping = {
'alpha': 'beta',
'beta': 'phi',
'gamma': 'psi',
'delta': 'chi'
}
rule_1 = Rule('alpha', 'phi')
rule_2 = Rule('gamma', 'beta')
rule_3 = Rule('delta', 'chi')
rule_4 = Rule('alpha', 'chi')
self.rules = {rule_1, rule_2, rule_3, rule_4}
self.bipolar_aba_framework = BipolarABA(
self.language, self.rules, self.assumptions,
self.assumptions_to_contrary_mapping)
def test_simple_preferred_extension_calculation(self):
preferred_extensions = list(
self.bipolar_aba_framework.get_preferred_extensions())
assert {'beta', 'gamma'} in preferred_extensions
assert {'alpha'} in preferred_extensions
assert len(preferred_extensions) == 2
def test_simple_set_stable_extension_calculation(self):
set_stable_extensions = list(
self.bipolar_aba_framework.get_set_stable_extensions())
assert {'alpha'} in set_stable_extensions
assert len(set_stable_extensions) == 1
def test_bipolar_aba_creation(language, rules, assumptions):
contrary_symbols = {a.contrary_symbol for a in assumptions}
try:
bipolar_aba_framework = BipolarABA(language, rules, assumptions)
assert bipolar_aba_framework.language == language
assert bipolar_aba_framework.rules == rules
assert bipolar_aba_framework.assumptions == assumptions
assert {c.symbol
for c in bipolar_aba_framework.contraries} == contrary_symbols
preferred_extensions = list(
bipolar_aba_framework.get_preferred_extensions())
for extension in preferred_extensions:
assert bipolar_aba_framework.is_closed(extension)
assert bipolar_aba_framework.is_conflict_free(extension)
assert bipolar_aba_framework.is_admissible_extension(extension)
for subset in strict_subsets(extension):
assert subset not in preferred_extensions
set_stable_extensions = list(
bipolar_aba_framework.get_set_stable_extensions())
for extension in set_stable_extensions:
assert extension in preferred_extensions
assert bipolar_aba_framework.is_closed(extension)
assert bipolar_aba_framework.is_conflict_free(extension)
assert bipolar_aba_framework.is_admissible_extension(extension)
for subset in strict_subsets(extension):
assert subset not in set_stable_extensions
assert subset not in preferred_extensions
except NonBipolarException as e:
if e.message == "The head of a rule in a BipolarABA framework must be an assumption or " \
"the contrary of an assumption.":
# assert any(r.consequent not in assumptions and r.consequent.symbol not in contrary_symbols for r in rules)
pass
elif e.message == "The body of a rule in a BipolarABA framework can only contain assumptions.":
assert any(a not in assumptions for r in rules
for a in r.antecedent)
elif e.message == "The body of a rule in a BipolarABA framework can only contain one sentence.":
assert any(len(r.antecedent) != 1 for r in rules)
elif e.message == "Assumptions in a BipolarABA framework should be part of the language.":
assert not assumptions <= language
elif e.message == "Contraries in a BipolarABA framework should be part of the language.":
symbols = {s.symbol for s in language}
assert not contrary_symbols <= symbols
else:
pytest.fail("Unexpected exception: " + e.message)