Fake Backends don't pass options to underlying simulator

Environment

• Qiskit Terra version: 0.19.x (and main)
• Python version: 3.10
• Operating system: linux

What is happening?

The options object from in the fake backends don’t get passed down to the underlying simulator.

How can we reproduce the issue?

from qiskit.circuit import QuantumCircuit
from qiskit import execute
from qiskit.test.mock import FakeQuito

backend = FakeQuito()
circuit = QuantumCircuit(2)
circuit.h(0)
circuit.cx(0, 1)
circuit.measure_all()
backend.set_options(shots=100)
job = execute(circuit, backend)
result = job.result()
counts = result.get_counts()
print(sum(counts.values())

What should happen?

100 should print not 1024

Any suggestions?

In the run() method defined in https://github.com/Qiskit/qiskit-terra/blob/main/qiskit/test/mock/fake_backend.py#L118 we should copy self.options and set the internal simulator backend object’s options attribute to be that copy. This will propagate any changes made by the user to the options to the underlying simulation when we call the internal simulator backend’s run() method.

[javabster]

Assigned to you @bopardikarsoham! Remember to read the contributing guidelines and let us know if you have any questions!

I think the unfinished sentence in “What is happening” is just a typo and there should be enough in the rest of the description for you to get started 😄

[1ucian0]

assigning you @VaibhavSanjay. Thanks!