def test_qexpr_commutative():
    q1 = QExpr(x)
    q2 = QExpr(y)
    assert q1.is_commutative is False
    assert q2.is_commutative is False
    assert q1*q2 != q2*q1

    q = QExpr._new_rawargs(0, 1, HilbertSpace())
    assert q.is_commutative is False

def test_qexpr_new():
    q = QExpr(0)
    assert q.label == (0,)
    assert q.hilbert_space == HilbertSpace()
    assert q.is_commutative is False

    q = QExpr(0, 1)
    assert q.label == (Integer(0), Integer(1))

    q = QExpr._new_rawargs(HilbertSpace(), Integer(0), Integer(1))
    assert q.label == (Integer(0), Integer(1))
    assert q.hilbert_space == HilbertSpace()

 def _eval_args(cls, args):
     args = QExpr._eval_args(args)
     if len(args) == 1:
         return args
     else:
         raise ValueError("Too many arguments")

 def _eval_args(cls, args):
     args = QExpr._eval_args(args)
     if len(args) != 3:
         raise ValueError("3 Euler angles required, got: %r" % args)
     return args

 def _eval_args(cls, args):
     # Fall back to this, because Gate._eval_args assumes that args is
     # all targets and can't contain duplicates.
     return QExpr._eval_args(args)

def test_qexpr_subs():
    q1 = QExpr(x, y)
    assert q1.subs(x, y) == QExpr(y, y)
    assert q1.subs({x: 1, y: 2}) == QExpr(1, 2)