def test_basic():
assert DisjNormalForm(set()) == 0
assert ConjNormalForm(set()) == 1
f = -a * b + a * -b
g = (a + b) * (-a + -b)
dnf = expr2nfexpr(f)
cnf = expr2nfexpr(g)
assert str(dnf) == "a' * b + a * b'"
assert str(cnf) == "(a + b) * (a' + b')"
assert repr(dnf) == "a' * b + a * b'"
assert repr(cnf) == "(a + b) * (a' + b')"
assert dnf.support == {a, b}
assert cnf.support == {a, b}
assert dnf.inputs == [a, b]
assert cnf.inputs == [a, b]
assert isinstance(-dnf, ConjNormalForm)
assert nfexpr2expr(-dnf).equivalent(-f)
assert isinstance(-cnf, DisjNormalForm)
assert nfexpr2expr(-cnf).equivalent(-g)
def test_conversion():
f = -a * b + a * -b
g = (a + b) * (-a + -b)
nose.tools.assert_raises(TypeError, expr2nfexpr, Xor(a, b))
nose.tools.assert_raises(TypeError, nfexpr2expr, "what?")
nfexpr2expr(expr2nfexpr(f)).equivalent(f)
nfexpr2expr(expr2nfexpr(g)).equivalent(g)