def test_sum() -> None:
x = qf.sX(1)
y = qf.sY(2, 2.0)
s = qf.pauli_sum(x, y)
assert s == qf.Pauli(([1], "X", 1.0), ([2], "Y", 2.0))
s2 = qf.pauli_sum(x, x)
assert s2 == qf.Pauli(([1], "X", 2))
s3 = qf.pauli_sum(x, x, y)
s4 = qf.pauli_sum(y, x, x)
assert s3 == s4
assert s3 == qf.Pauli(([1], "X", 2), ([2], "Y", 2))
qf.pauli_sum(x, x, x)
def test_sub() -> None:
x = sX(1)
y = sY(2, 2.0)
s = x - y
assert s == qf.Pauli(([1], "X", 1), ([2], "Y", -2))
s = 2 - y
assert str(s) == "+(2+0j) +(-2+0j) sY(2)"
def test_merge_sum():
p = qf.pauli_sum(qf.Pauli(((((1, 'Y'),), (3+0j)),)),
qf.Pauli(((((1, 'Y'),), (2+0j)),)))
assert len(p) == 1
assert p.terms[0][1] == 5
def test_add() -> None:
x = sX(1)
y = sY(2, 2.0)
s = y + x
assert s == qf.Pauli(([1], "X", 1), ([2], "Y", 2))