from qiskit.providers.basic_provider import BasicSimulator

from quantum_learning.experiments import (
    bell_circuit,
    build_demo_noise_model,
    line_coupling_map,
    simulate_counts,
    transpile_summary,
)


def test_simulate_counts_respects_requested_shots():
    counts = simulate_counts(bell_circuit(), shots=64, seed=13)
    assert sum(counts.values()) == 64


def test_transpile_summary_returns_compiled_circuit():
    circuit = bell_circuit(measure=False)
    backend = BasicSimulator()
    summary = transpile_summary(
        circuit,
        backend,
        basis_gates=["rz", "sx", "x", "cx"],
        coupling_map=line_coupling_map(2),
    )

    assert summary["depth_before"] >= 1
    assert summary["compiled_circuit"].num_qubits == 2
    assert summary["ops_after"]


def test_build_demo_noise_model_declares_cx_basis_gate():
    noise_model = build_demo_noise_model()
    assert "cx" in noise_model.basis_gates


def test_simulate_counts_with_noise_still_returns_requested_shots():
    counts = simulate_counts(
        bell_circuit(),
        shots=64,
        seed=11,
        noise_model=build_demo_noise_model(readout_error=0.1),
    )
    assert sum(counts.values()) == 64