def test_to_expr():
bdd = _bdd.BDD()
bdd.declare('x', 'y')
u = bdd.add_expr('x')
s = bdd.to_expr(u)
assert s == 'x', s
u = bdd.add_expr('x /\ y')
s = bdd.to_expr(u)
assert s == 'ite(x, y, FALSE)', s
def test_copy_bdd():
bdd = _bdd.BDD()
other = _bdd.BDD()
bdd.declare('x')
other.declare('x')
u = bdd.var('x')
v = _bdd.copy_bdd(u, other)
v_ = other.var('x')
assert v == v_, other.to_expr(v)
# involution
u_ = _bdd.copy_bdd(v, bdd)
assert u == u_, bdd.to_expr(u_)