def test_qubit_not_mutated():
qubit = cirq.GridQubit(0, 0)
above(qubit)
assert qubit == cirq.GridQubit(0, 0)
below(qubit)
assert qubit == cirq.GridQubit(0, 0)
right_of(qubit)
assert qubit == cirq.GridQubit(0, 0)
left_of(qubit)
assert qubit == cirq.GridQubit(0, 0)
def test_neighbours():
qubit = cirq.GridQubit(0, 0)
assert above(qubit) == cirq.GridQubit(0, -1)
assert below(qubit) == cirq.GridQubit(0, 1)
assert right_of(qubit) == cirq.GridQubit(1, 0)
assert left_of(qubit) == cirq.GridQubit(-1, 0)