def test_unsat():
cnf = read_dimacs("""
p cnf 1 2
1 0
-1 0
""")
with pytest.raises(Unsatisfiable):
cdcl(cnf)
def test_sat():
cnf = read_dimacs("""
p cnf 3 3
-1 -2 3 0
-1 2 0
1 0
""")
assert cdcl(cnf) == {1: True, 2: True, 3: True}
def test_with_state():
cnf = read_dimacs("""
p cnf 2 1
1 2 0
""")
assert unit_resolution_once(cnf, [Var(name=1, val=False)]) == [
Var(name=1, val=False), Var(name=2, val=True)
]
def test_sat():
cnf = read_dimacs("""
p cnf 3 3
-1 -2 3 0
-1 2 0
1 0
""")
assert unit_resolution(cnf, []) == [Var(1, True), Var(2, True), Var(3, True)]
def test_unsat_with_state():
cnf = read_dimacs("""
p cnf 2 1
1 2 0
""")
with pytest.raises(Unsatisfiable):
unit_resolution_once(cnf,
[Var(name=1, val=False),
Var(name=2, val=False)])
def test_only_single_variable():
cnf = read_dimacs("""
p cnf 1 1
1 0
""")
assert unit_resolution_once(cnf, []) == [Var(name=1, val=True)]
cnf = read_dimacs("""
p cnf 1 1
-1 0
""")
assert unit_resolution_once(cnf, []) == [Var(name=1, val=False)]
cnf = read_dimacs("""
p cnf 1 1
1 0
""")
assert unit_resolution_once(cnf, []) == [Var(name=1, val=True)]
def test_unsat():
cnf = read_dimacs("""
p cnf 2 3
1 -2 0
-1 -2 0
2 0
""")
with pytest.raises(Unsatisfiable):
print(unit_resolution(cnf, []))
def test_read_dimacs():
# test simplest DIMACS .cnf file
dimacs = """p cnf 1 1
1 0"""
assert read_dimacs(dimacs) == [
{1: True},
]
# test DIMACS with negation
dimacs = """p cnf 1 1
-1 0"""
assert read_dimacs(dimacs) == [
{1: False},
]
# test comments
dimacs = """
c Just comment
p cnf 1 1
-1 0"""
assert read_dimacs(dimacs) == [
{1: False},
]
# test complicated CNF
dimacs = """
c A sample .cnf file.
p cnf 3 2
1 -3 0
2 3 -1 0"""
assert read_dimacs(dimacs) == [
{1: True, 3: False},
{2: True, 3: True, 1: False}
]
# test basic unsatisfiable cnf
dimacs = """
c A sample .cnf file.
p cnf 1 1
1 -1 0"""
with pytest.raises(Unsatisfiable):
read_dimacs(dimacs)
def test_without_single_variable():
cnf = read_dimacs("""
p cnf 2 1
1 2 0
""")
assert unit_resolution_once(cnf, []) == []