def test_pl_true():
assert pl_true(True) is True
assert pl_true( A & B, {A: True, B: True}) is True
assert pl_true( A | B, {A: True}) is True
assert pl_true( A | B, {B: True}) is True
assert pl_true( A | B, {A: None, B: True}) is True
assert pl_true( A >> B, {A: False}) is True
assert pl_true( A | B | ~C, {A: False, B: True, C: True}) is True
assert pl_true(Equivalent(A, B), {A: False, B: False}) is True
# test for false
assert pl_true(False) is False
assert pl_true( A & B, {A: False, B: False}) is False
assert pl_true( A & B, {A: False}) is False
assert pl_true( A & B, {B: False}) is False
assert pl_true( A | B, {A: False, B: False}) is False
# test for None
assert pl_true(B, {B: None}) is None
assert pl_true( A & B, {A: True, B: None}) is None
assert pl_true( A >> B, {A: True, B: None}) is None
assert pl_true(Equivalent(A, B), {A: None}) is None
assert pl_true(Equivalent(A, B), {A: True, B: None}) is None
# Test for deep
assert pl_true(A | B, {A: False}, deep=True) is None
assert pl_true(~A & ~B, {A: False}, deep=True) is None
assert pl_true(A | B, {A: False, B: False}, deep=True) is False
assert pl_true(A & B & (~A | ~B), {A: True}, deep=True) is False
assert pl_true((C >> A) >> (B >> A), {C: True}, deep=True) is True
def test_to_nnf():
assert to_nnf(true) is true
assert to_nnf(false) is false
assert to_nnf(A) == A
assert (~A).to_nnf() == ~A
class Boo(BooleanFunction):
pass
pytest.raises(ValueError, lambda: to_nnf(~Boo(A)))
assert to_nnf(A | ~A | B) is true
assert to_nnf(A & ~A & B) is false
assert to_nnf(A >> B) == ~A | B
assert to_nnf(Equivalent(A, B, C)) == (~A | B) & (~B | C) & (~C | A)
assert to_nnf(A ^ B ^ C) == \
(A | B | C) & (~A | ~B | C) & (A | ~B | ~C) & (~A | B | ~C)
assert to_nnf(ITE(A, B, C)) == (~A | B) & (A | C)
assert to_nnf(Not(A | B | C)) == ~A & ~B & ~C
assert to_nnf(Not(A & B & C)) == ~A | ~B | ~C
assert to_nnf(Not(A >> B)) == A & ~B
assert to_nnf(Not(Equivalent(A, B, C))) == And(Or(A, B, C), Or(~A, ~B, ~C))
assert to_nnf(Not(A ^ B ^ C)) == \
(~A | B | C) & (A | ~B | C) & (A | B | ~C) & (~A | ~B | ~C)
assert to_nnf(Not(ITE(A, B, C))) == (~A | ~B) & (A | ~C)
assert to_nnf((A >> B) ^ (B >> A)) == (A & ~B) | (~A & B)
assert to_nnf((A >> B) ^ (B >> A), False) == \
(~A | ~B | A | B) & ((A & ~B) | (~A & B))
def test_dpll_satisfiable():
A, B, C = symbols('A,B,C')
assert dpll_satisfiable(A & ~A) is False
assert dpll_satisfiable(A & ~B) == {A: True, B: False}
assert dpll_satisfiable(A | B) in ({
A: True
}, {
B: True
}, {
A: True,
B: True
})
assert dpll_satisfiable((~A | B) & (~B | A)) in ({
A: True,
B: True
}, {
A: False,
B: False
})
assert dpll_satisfiable((A | B) & (~B | C)) in ({
A: True,
B: False
}, {
A: True,
C: True
}, {
B: True,
C: True
})
assert dpll_satisfiable(A & B & C) == {A: True, B: True, C: True}
assert dpll_satisfiable((A | B) & (A >> B)) == {B: True}
assert dpll_satisfiable(Equivalent(A, B) & A) == {A: True, B: True}
assert dpll_satisfiable(Equivalent(A, B) & ~A) == {A: False, B: False}
def test_to_dnf():
assert to_dnf(true) == true
assert to_dnf((~B) & (~C)) == (~B) & (~C)
assert to_dnf(~(B | C)) == And(Not(B), Not(C))
assert to_dnf(A & (B | C)) == Or(And(A, B), And(A, C))
assert to_dnf(A >> B) == (~A) | B
assert to_dnf(A >> (B & C)) == (~A) | (B & C)
assert to_dnf(Equivalent(A, B), True) == \
Or(And(A, B), And(Not(A), Not(B)))
assert to_dnf(Equivalent(A, B & C), True) == \
Or(And(A, B, C), And(Not(A), Not(B)), And(Not(A), Not(C)))
def test_to_cnf():
assert to_cnf(~(B | C)) == And(Not(B), Not(C))
assert to_cnf((A & B) | C) == And(Or(A, C), Or(B, C))
assert to_cnf(A >> B) == (~A) | B
assert to_cnf(A >> (B & C)) == (~A | B) & (~A | C)
assert to_cnf(A & (B | C) | ~A & (B | C), True) == B | C
assert to_cnf(Equivalent(A, B)) == And(Or(A, Not(B)), Or(B, Not(A)))
assert to_cnf(Equivalent(A, B & C)) == \
(~A | B) & (~A | C) & (~B | ~C | A)
assert to_cnf(Equivalent(A, B | C), True) == \
And(Or(Not(B), A), Or(Not(C), A), Or(B, C, Not(A)))
def test_equals():
assert Not(Or(A, B)).equals( And(Not(A), Not(B)) ) is True
assert Equivalent(A, B).equals((A >> B) & (B >> A)) is True
assert ((A | ~B) & (~A | B)).equals((~A & ~B) | (A & B)) is True
assert (A >> B).equals(~A >> ~B) is False
assert (A >> (B >> A)).equals(A >> (C >> A)) is False
pytest.raises(NotImplementedError, lambda: And(A, A < B).equals(And(A, B > A)))
def test_eliminate_implications():
from diofant.abc import A, B, C, D
assert eliminate_implications(Implies(A, B, evaluate=False)) == (~A) | B
assert eliminate_implications(A >> (C >> Not(B))) == Or(
Or(Not(B), Not(C)), Not(A))
assert eliminate_implications(Equivalent(A, B, C, D)) == \
(~A | B) & (~B | C) & (~C | D) & (~D | A)
def test_satisfiable_all_models():
assert next(satisfiable(False, all_models=True)) is False
assert list(satisfiable((A >> ~A) & A, all_models=True)) == [False]
assert list(satisfiable(True, all_models=True)) == [{true: true}]
models = [{A: True, B: False}, {A: False, B: True}]
result = satisfiable(A ^ B, all_models=True)
models.remove(next(result))
models.remove(next(result))
pytest.raises(StopIteration, lambda: next(result))
assert not models
assert list(satisfiable(Equivalent(A, B), all_models=True)) == \
[{A: False, B: False}, {A: True, B: True}]
models = [{A: False, B: False}, {A: False, B: True}, {A: True, B: True}]
for model in satisfiable(A >> B, all_models=True):
models.remove(model)
assert not models
# This is a santiy test to check that only the required number
# of solutions are generated. The expr below has 2**100 - 1 models
# which would time out the test if all are generated at once.
sym = numbered_symbols()
X = [next(sym) for i in range(100)]
result = satisfiable(Or(*X), all_models=True)
for i in range(10):
assert next(result)
def test_fcode_precedence():
assert fcode(And(x < y, y < x + 1), source_format="free") == \
"x < y .and. y < x + 1"
assert fcode(Or(x < y, y < x + 1), source_format="free") == \
"x < y .or. y < x + 1"
assert fcode(Xor(x < y, y < x + 1, evaluate=False),
source_format="free") == "x < y .neqv. y < x + 1"
assert fcode(Equivalent(x < y, y < x + 1), source_format="free") == \
"x < y .eqv. y < x + 1"
def test_dpll2_satisfiable():
assert dpll2_satisfiable( A & ~A ) is False
assert dpll2_satisfiable( A & ~B ) == {A: True, B: False}
assert dpll2_satisfiable(
A | B ) in ({A: True}, {B: True}, {A: True, B: True})
assert dpll2_satisfiable(
(~A | B) & (~B | A) ) in ({A: True, B: True}, {A: False, B: False})
assert dpll2_satisfiable( (A | B) & (~B | C) ) in ({A: True, B: False, C: True},
{A: True, B: True, C: True})
assert dpll2_satisfiable( A & B & C ) == {A: True, B: True, C: True}
assert dpll2_satisfiable( (A | B) & (A >> B) ) in ({B: True, A: False},
{B: True, A: True})
assert dpll2_satisfiable( Equivalent(A, B) & A ) == {A: True, B: True}
assert dpll2_satisfiable( Equivalent(A, B) & ~A ) == {A: False, B: False}
l = SATSolver([], set(), set())
assert l.lit_heap == []
assert l._vsids_calculate() == 0
def test_simplification():
"""
Test working of simplification methods.
"""
set1 = [[0, 0, 1], [0, 1, 1], [1, 0, 0], [1, 1, 0]]
set2 = [[0, 0, 0], [0, 1, 0], [1, 0, 1], [1, 1, 1]]
from diofant.abc import w, x, y, z
assert SOPform([x, y, z], set1) == Or(And(Not(x), z), And(Not(z), x))
assert Not(SOPform([x, y, z],
set2)) == Not(Or(And(Not(x), Not(z)), And(x, z)))
assert POSform([x, y, z], set1 + set2) is true
assert SOPform([x, y, z], set1 + set2) is true
assert SOPform([Dummy(), Dummy(), Dummy()], set1 + set2) is true
minterms = [[0, 0, 0, 1], [0, 0, 1, 1], [0, 1, 1, 1], [1, 0, 1, 1],
[1, 1, 1, 1]]
dontcares = [[0, 0, 0, 0], [0, 0, 1, 0], [0, 1, 0, 1]]
assert (SOPform([w, x, y, z], minterms,
dontcares) == Or(And(Not(w), z), And(y, z)))
assert POSform([w, x, y, z], minterms, dontcares) == And(Or(Not(w), y), z)
# test simplification
ans = And(A, Or(B, C))
assert simplify_logic(A & (B | C)) == ans
assert simplify_logic((A & B) | (A & C)) == ans
assert simplify_logic(Implies(A, B)) == Or(Not(A), B)
assert simplify_logic(Equivalent(A, B)) == \
Or(And(A, B), And(Not(A), Not(B)))
assert simplify_logic(And(Equality(A, 2), C)) == And(Equality(A, 2), C)
assert simplify_logic(And(Equality(A, 2), A)) == And(Equality(A, 2), A)
assert simplify_logic(And(Equality(A, B), C)) == And(Equality(A, B), C)
assert simplify_logic(Or(And(Equality(A, 3), B), And(Equality(A, 3), C))) \
== And(Equality(A, 3), Or(B, C))
e = And(A, x**2 - x)
assert simplify_logic(e) == And(A, x * (x - 1))
assert simplify_logic(e, deep=False) == e
# check input
ans = SOPform([x, y], [[1, 0]])
assert SOPform([x, y], [[1, 0]]) == ans
assert POSform([x, y], [[1, 0]]) == ans
pytest.raises(ValueError, lambda: SOPform([x], [[1]], [[1]]))
assert SOPform([x], [[1]], [[0]]) is true
assert SOPform([x], [[0]], [[1]]) is true
assert SOPform([x], [], []) is false
pytest.raises(ValueError, lambda: POSform([x], [[1]], [[1]]))
assert POSform([x], [[1]], [[0]]) is true
assert POSform([x], [[0]], [[1]]) is true
assert POSform([x], [], []) is false
# check working of simplify
assert simplify((A & B) | (A & C)) == And(A, Or(B, C))
assert simplify(And(x, Not(x))) is S.false
assert simplify(Or(x, Not(x))) is S.true
def test_dpll2_satisfiable():
A, B, C = symbols('A,B,C')
assert dpll2_satisfiable( A & ~A ) is False
assert dpll2_satisfiable( A & ~B ) == {A: True, B: False}
assert dpll2_satisfiable(
A | B ) in ({A: True}, {B: True}, {A: True, B: True})
assert dpll2_satisfiable(
(~A | B) & (~B | A) ) in ({A: True, B: True}, {A: False, B: False})
assert dpll2_satisfiable( (A | B) & (~B | C) ) in ({A: True, B: False, C: True},
{A: True, B: True, C: True})
assert dpll2_satisfiable( A & B & C ) == {A: True, B: True, C: True}
assert dpll2_satisfiable( (A | B) & (A >> B) ) in ({B: True, A: False},
{B: True, A: True})
assert dpll2_satisfiable( Equivalent(A, B) & A ) == {A: True, B: True}
assert dpll2_satisfiable( Equivalent(A, B) & ~A ) == {A: False, B: False}
from diofant.logic.algorithms.dpll2 import SATSolver
l = SATSolver([], set(), set())
assert l.lit_heap == []
assert l._vsids_calculate() == 0
def test_dpll2_satisfiable():
assert dpll2_satisfiable(A & ~A) is False
assert dpll2_satisfiable(A & ~B) == {A: True, B: False}
assert dpll2_satisfiable(A | B) in ({
A: True
}, {
B: True
}, {
A: True,
B: True
})
assert dpll2_satisfiable((~A | B) & (~B | A)) in ({
A: True,
B: True
}, {
A: False,
B: False
})
assert dpll2_satisfiable((A | B) & (~B | C)) in ({
A: True,
B: False,
C: True
}, {
A: True,
B: True,
C: True
})
assert dpll2_satisfiable(A & B & C) == {A: True, B: True, C: True}
assert dpll2_satisfiable((A | B) & (A >> B)) in ({
B: True,
A: False
}, {
B: True,
A: True
})
assert dpll2_satisfiable(Equivalent(A, B) & A) == {A: True, B: True}
assert dpll2_satisfiable(Equivalent(A, B) & ~A) == {A: False, B: False}
l = SATSolver([], set(), set())
assert l.lit_heap == []
assert l._vsids_calculate() == 0
l0 = SATSolver([{2, -3}, {1}, {3, -3}, {2, -2}, {3, -2}], {1, 2, 3}, set())
l = copy.deepcopy(l0)
assert l.num_learned_clauses == 0
assert l.lit_scores == {
-3: -2.0,
-2: -2.0,
-1: 0.0,
1: 0.0,
2: -2.0,
3: -2.0
}
l._vsids_clause_added({2, -3})
assert l.num_learned_clauses == 1
assert l.lit_scores == {
-3: -1.0,
-2: -2.0,
-1: 0.0,
1: 0.0,
2: -1.0,
3: -2.0
}
l = copy.deepcopy(l0)
assert l.num_learned_clauses == 0
assert l.clauses == [[2, -3], [1], [3, -3], [2, -2], [3, -2]]
assert l.sentinels == {-3: {0, 2}, -2: {3, 4}, 2: {0, 3}, 3: {2, 4}}
l._simple_add_learned_clause([3])
assert l.clauses == [[2, -3], [1], [3, -3], [2, -2], [3, -2], [3]]
assert l.sentinels == {-3: {0, 2}, -2: {3, 4}, 2: {0, 3}, 3: {2, 4, 5}}
l = copy.deepcopy(l0)
assert l.lit_scores == {
-3: -2.0,
-2: -2.0,
-1: 0.0,
1: 0.0,
2: -2.0,
3: -2.0
}
l._vsids_decay()
assert l.lit_scores == {
-3: -1.0,
-2: -1.0,
-1: 0.0,
1: 0.0,
2: -1.0,
3: -1.0
}
l = copy.deepcopy(l0)
assert next(l._find_model()) == {1: True, 2: False, 3: False}
assert l._simple_compute_conflict() == [3]
def test_fcode_Xlogical():
# binary Xor
assert fcode(Xor(x, y, evaluate=False), source_format="free") == \
"x .neqv. y"
assert fcode(Xor(x, Not(y), evaluate=False), source_format="free") == \
"x .neqv. .not. y"
assert fcode(Xor(Not(x), y, evaluate=False), source_format="free") == \
"y .neqv. .not. x"
assert fcode(Xor(Not(x), Not(y), evaluate=False),
source_format="free") == ".not. x .neqv. .not. y"
assert fcode(Not(Xor(x, y, evaluate=False), evaluate=False),
source_format="free") == ".not. (x .neqv. y)"
# binary Equivalent
assert fcode(Equivalent(x, y), source_format="free") == "x .eqv. y"
assert fcode(Equivalent(x, Not(y)), source_format="free") == \
"x .eqv. .not. y"
assert fcode(Equivalent(Not(x), y), source_format="free") == \
"y .eqv. .not. x"
assert fcode(Equivalent(Not(x), Not(y)), source_format="free") == \
".not. x .eqv. .not. y"
assert fcode(Not(Equivalent(x, y), evaluate=False),
source_format="free") == ".not. (x .eqv. y)"
# mixed And/Equivalent
assert fcode(Equivalent(And(y, z), x), source_format="free") == \
"x .eqv. y .and. z"
assert fcode(Equivalent(And(z, x), y), source_format="free") == \
"y .eqv. x .and. z"
assert fcode(Equivalent(And(x, y), z), source_format="free") == \
"z .eqv. x .and. y"
assert fcode(And(Equivalent(y, z), x), source_format="free") == \
"x .and. (y .eqv. z)"
assert fcode(And(Equivalent(z, x), y), source_format="free") == \
"y .and. (x .eqv. z)"
assert fcode(And(Equivalent(x, y), z), source_format="free") == \
"z .and. (x .eqv. y)"
# mixed Or/Equivalent
assert fcode(Equivalent(Or(y, z), x), source_format="free") == \
"x .eqv. y .or. z"
assert fcode(Equivalent(Or(z, x), y), source_format="free") == \
"y .eqv. x .or. z"
assert fcode(Equivalent(Or(x, y), z), source_format="free") == \
"z .eqv. x .or. y"
assert fcode(Or(Equivalent(y, z), x), source_format="free") == \
"x .or. (y .eqv. z)"
assert fcode(Or(Equivalent(z, x), y), source_format="free") == \
"y .or. (x .eqv. z)"
assert fcode(Or(Equivalent(x, y), z), source_format="free") == \
"z .or. (x .eqv. y)"
# mixed Xor/Equivalent
assert fcode(Equivalent(Xor(y, z, evaluate=False), x),
source_format="free") == "x .eqv. (y .neqv. z)"
assert fcode(Equivalent(Xor(z, x, evaluate=False), y),
source_format="free") == "y .eqv. (x .neqv. z)"
assert fcode(Equivalent(Xor(x, y, evaluate=False), z),
source_format="free") == "z .eqv. (x .neqv. y)"
assert fcode(Xor(Equivalent(y, z), x, evaluate=False),
source_format="free") == "x .neqv. (y .eqv. z)"
assert fcode(Xor(Equivalent(z, x), y, evaluate=False),
source_format="free") == "y .neqv. (x .eqv. z)"
assert fcode(Xor(Equivalent(x, y), z, evaluate=False),
source_format="free") == "z .neqv. (x .eqv. y)"
# mixed And/Xor
assert fcode(Xor(And(y, z), x, evaluate=False), source_format="free") == \
"x .neqv. y .and. z"
assert fcode(Xor(And(z, x), y, evaluate=False), source_format="free") == \
"y .neqv. x .and. z"
assert fcode(Xor(And(x, y), z, evaluate=False), source_format="free") == \
"z .neqv. x .and. y"
assert fcode(And(Xor(y, z, evaluate=False), x), source_format="free") == \
"x .and. (y .neqv. z)"
assert fcode(And(Xor(z, x, evaluate=False), y), source_format="free") == \
"y .and. (x .neqv. z)"
assert fcode(And(Xor(x, y, evaluate=False), z), source_format="free") == \
"z .and. (x .neqv. y)"
# mixed Or/Xor
assert fcode(Xor(Or(y, z), x, evaluate=False), source_format="free") == \
"x .neqv. y .or. z"
assert fcode(Xor(Or(z, x), y, evaluate=False), source_format="free") == \
"y .neqv. x .or. z"
assert fcode(Xor(Or(x, y), z, evaluate=False), source_format="free") == \
"z .neqv. x .or. y"
assert fcode(Or(Xor(y, z, evaluate=False), x), source_format="free") == \
"x .or. (y .neqv. z)"
assert fcode(Or(Xor(z, x, evaluate=False), y), source_format="free") == \
"y .or. (x .neqv. z)"
assert fcode(Or(Xor(x, y, evaluate=False), z), source_format="free") == \
"z .or. (x .neqv. y)"
# trinary Xor
assert fcode(Xor(x, y, z, evaluate=False), source_format="free") == \
"x .neqv. y .neqv. z"
assert fcode(Xor(x, y, Not(z), evaluate=False), source_format="free") == \
"x .neqv. y .neqv. .not. z"
assert fcode(Xor(x, Not(y), z, evaluate=False), source_format="free") == \
"x .neqv. z .neqv. .not. y"
assert fcode(Xor(Not(x), y, z, evaluate=False), source_format="free") == \
"y .neqv. z .neqv. .not. x"
def test_Equivalent():
assert Equivalent(A, B) == Equivalent(B, A) == Equivalent(A, B, A)
assert Equivalent() is true
assert Equivalent(A, A) == Equivalent(A) is true
assert Equivalent(True, True) == Equivalent(False, False) is true
assert Equivalent(True, False) == Equivalent(False, True) is false
assert Equivalent(A, True) == A
assert Equivalent(A, False) == Not(A)
assert Equivalent(A, B, True) == A & B
assert Equivalent(A, B, False) == ~A & ~B
assert Equivalent(1, A) == A
assert Equivalent(0, A) == Not(A)
assert Equivalent(A, Equivalent(B, C)) != Equivalent(Equivalent(A, B), C)
assert Equivalent(A < 1, A >= 1) is false
assert Equivalent(A < 1, A >= 1, 0) is false
assert Equivalent(A < 1, A >= 1, 1) is false
assert Equivalent(A < 1,
Integer(1) > A) == Equivalent(1, 1) == Equivalent(0, 0)
assert Equivalent(A < 1, B >= 1) == Equivalent(B >= 1,
A < 1,
evaluate=False)
def test_entails():
assert entails(A, [A >> B, ~B]) is False
assert entails(B, [Equivalent(A, B), A]) is True
assert entails((A >> B) >> (~A >> ~B)) is False
assert entails((A >> B) >> (~B >> ~A)) is True
def test_true_false():
assert true is true
assert false is false
assert true is not True
assert false is not False
assert true
assert not false
assert true == True # noqa: E712
assert false == False # noqa: E712
assert not (true == False) # noqa: E712
assert not (false == True) # noqa: E712
assert not (true == false)
assert hash(true) == hash(True)
assert hash(false) == hash(False)
assert len({true, True}) == len({false, False}) == 1
assert isinstance(true, BooleanAtom)
assert isinstance(false, BooleanAtom)
# We don't want to subclass from bool, because bool subclasses from
# int. But operators like &, |, ^, <<, >>, and ~ act differently on 0 and
# 1 then we want them to on true and false. See the docstrings of the
# various And, Or, etc. functions for examples.
assert not isinstance(true, bool)
assert not isinstance(false, bool)
# Note: using 'is' comparison is important here. We want these to return
# true and false, not True and False
assert Not(true) is false
assert Not(True) is false
assert Not(false) is true
assert Not(False) is true
assert ~true is false
assert ~false is true
for T, F in itertools.product([True, true], [False, false]):
assert And(T, F) is false
assert And(F, T) is false
assert And(F, F) is false
assert And(T, T) is true
assert And(T, x) == x
assert And(F, x) is false
if not (T is True and F is False):
assert T & F is false
assert F & T is false
if F is not False:
assert F & F is false
if T is not True:
assert T & T is true
assert Or(T, F) is true
assert Or(F, T) is true
assert Or(F, F) is false
assert Or(T, T) is true
assert Or(T, x) is true
assert Or(F, x) == x
if not (T is True and F is False):
assert T | F is true
assert F | T is true
if F is not False:
assert F | F is false
if T is not True:
assert T | T is true
assert Xor(T, F) is true
assert Xor(F, T) is true
assert Xor(F, F) is false
assert Xor(T, T) is false
assert Xor(T, x) == ~x
assert Xor(F, x) == x
if not (T is True and F is False):
assert T ^ F is true
assert F ^ T is true
if F is not False:
assert F ^ F is false
if T is not True:
assert T ^ T is false
assert Nand(T, F) is true
assert Nand(F, T) is true
assert Nand(F, F) is true
assert Nand(T, T) is false
assert Nand(T, x) == ~x
assert Nand(F, x) is true
assert Nor(T, F) is false
assert Nor(F, T) is false
assert Nor(F, F) is true
assert Nor(T, T) is false
assert Nor(T, x) is false
assert Nor(F, x) == ~x
assert Implies(T, F) is false
assert Implies(F, T) is true
assert Implies(F, F) is true
assert Implies(T, T) is true
assert Implies(T, x) == x
assert Implies(F, x) is true
assert Implies(x, T) is true
assert Implies(x, F) == ~x
if not (T is True and F is False):
assert T >> F is false
assert F << T is false
assert F >> T is true
assert T << F is true
if F is not False:
assert F >> F is true
assert F << F is true
if T is not True:
assert T >> T is true
assert T << T is true
assert Equivalent(T, F) is false
assert Equivalent(F, T) is false
assert Equivalent(F, F) is true
assert Equivalent(T, T) is true
assert Equivalent(T, x) == x
assert Equivalent(F, x) == ~x
assert Equivalent(x, T) == x
assert Equivalent(x, F) == ~x
assert ITE(T, T, T) is true
assert ITE(T, T, F) is true
assert ITE(T, F, T) is false
assert ITE(T, F, F) is false
assert ITE(F, T, T) is true
assert ITE(F, T, F) is false
assert ITE(F, F, T) is true
assert ITE(F, F, F) is false
