bugfix: Handle meas_level from backend.run (#142)

* Validate meas_level if it is supplied to run, and if it's valid, remove it. AwsQuantumTask does not accept meas_level argument

qiskit_braket_provider/providers/braket_backend.py

@@ -3,6 +3,7 @@
 
 import datetime
 import logging
+import enum
 from abc import ABC
 from typing import Iterable, Union, List
 
@@ -36,6 +37,15 @@ class BraketBackend(BackendV2, ABC):
     def __repr__(self):
         return f"BraketBackend[{self.name}]"
 
+    def _validate_meas_level(self, meas_level: Union[enum.Enum, int]):
+        if isinstance(meas_level, enum.Enum):
+            meas_level = meas_level.value
+        if meas_level != 2:
+            raise QiskitBraketException(
+                f"Device {self.name} only supports classified measurement "
+                f"results, received meas_level={meas_level}."
+            )
+
 
 class BraketLocalBackend(BraketBackend):
     """BraketLocalBackend."""
@@ -109,6 +119,9 @@ def run(
         shots = options["shots"] if "shots" in options else 1024
         if shots == 0:
             circuits = list(map(lambda x: x.state_vector(), circuits))
+        if "meas_level" in options:
+            self._validate_meas_level(options["meas_level"])
+            del options["meas_level"]
         tasks = []
         try:
             for circuit in circuits:
@@ -278,6 +291,10 @@ def run(self, run_input, **options):
         else:
             raise QiskitBraketException(f"Unsupported input type: {type(run_input)}")
 
+        if "meas_level" in options:
+            self._validate_meas_level(options["meas_level"])
+            del options["meas_level"]
+
         braket_circuits = list(convert_qiskit_to_braket_circuits(circuits))
 
         if options.pop("verbatim", False):

tests/providers/test_adapter.py

@@ -10,11 +10,11 @@
 
 from qiskit import (
     QuantumCircuit,
-    BasicAer,
     QuantumRegister,
     ClassicalRegister,
     transpile,
 )
+from qiskit.providers.basicaer import BasicAer
 from qiskit.circuit import Parameter
 from qiskit.circuit.library import PauliEvolutionGate
 from qiskit.quantum_info import SparsePauliOp

tests/providers/test_braket_backend.py

@@ -6,7 +6,8 @@
 
 from botocore import errorfactory
 from braket.aws.queue_information import QueueDepthInfo, QueueType
-from qiskit import QuantumCircuit, transpile, BasicAer
+from qiskit import QuantumCircuit, transpile
+from qiskit.providers.basicaer import BasicAer
 
 from qiskit.algorithms.minimum_eigensolvers import VQE, VQEResult
 
@@ -20,7 +21,7 @@
 from qiskit.transpiler import Target
 from qiskit.primitives import BackendEstimator
 
-from qiskit_braket_provider import AWSBraketProvider, version
+from qiskit_braket_provider import AWSBraketProvider, version, exception
 from qiskit_braket_provider.providers import AWSBraketBackend, BraketLocalBackend
 from qiskit_braket_provider.providers.adapter import aws_device_to_target
 from tests.providers.mocks import (
@@ -141,6 +142,23 @@ def test_local_backend_circuit_shots0(self):
         self.assertEqual(statevector[2], 0.0 + 0.0j)
         self.assertEqual(statevector[3], 1.0 + 0.0j)
 
+    def test_meas_level_2(self):
+        """Check that there's no error for asking for classified measurement results."""
+        backend = BraketLocalBackend(name="default")
+        circuit = QuantumCircuit(1, 1)
+        circuit.h(0)
+        circuit.measure(0, 0)
+        backend.run(circuit, shots=10, meas_level=2)
+
+    def test_meas_level_1(self):
+        """Check that there's an exception for asking for raw measurement results."""
+        backend = BraketLocalBackend(name="default")
+        circuit = QuantumCircuit(1, 1)
+        circuit.h(0)
+        circuit.measure(0, 0)
+        with self.assertRaises(exception.QiskitBraketException):
+            backend.run(circuit, shots=10, meas_level=1)
+
     def test_vqe(self):
         """Tests VQE."""
         local_simulator = BraketLocalBackend(name="default")