Update circuit helper methods to handle list of size one

qiskit_ionq/helpers.py

@@ -113,21 +113,33 @@
 def qiskit_circ_to_ionq_circ(input_circuit):
     """Build a circuit in IonQ's instruction format from qiskit instructions.
 
+    .. NOTE::
+        IonQ backends do not support multi-experiment jobs.
+        If ``input_circuit`` is provided as a list with more than one element
+        then this method will raise out with a RuntimeError.
+
     .. ATTENTION:: This function ignores the following compiler directives:
        * ``barrier``
 
     Parameters:
-        circ (:class:`QuantumCircuit <qiskit.circuit.QuantumCircuit>`): A quantum circuit.
+        input_circuit (:class:`QuantumCircuit <qiskit.circuit.QuantumCircuit>`): A quantum circuit.
 
     Raises:
         IonQGateError: If an unsupported instruction is supplied.
         IonQMidCircuitMeasurementError: If a mid-circuit measurement is detected.
+        RuntimeError: If a multi-experiment circuit was provided.
 
     Returns:
         list[dict]: A list of instructions in a converted dict format.
         int: The number of measurements.
         dict: The measurement map from qubit number to classical bit number.
     """
+
+    if isinstance(input_circuit, (list, tuple)):
+        if len(input_circuit) > 1:
+            raise RuntimeError("Multi-experiment jobs are not supported!")
+        input_circuit = input_circuit[0]
+
     compiler_directives = ["barrier"]
     output_circuit = []
     num_meas = 0
@@ -295,14 +307,28 @@ def decompress_metadata_string_to_dict(input_string):  # pylint: disable=invalid
 def qiskit_to_ionq(circuit, backend_name, passed_args=None):
     """Convert a Qiskit circuit to a IonQ compatible dict.
 
+    .. NOTE::
+        IonQ backends do not support multi-experiment jobs.
+        If ``circuit`` is provided as a list with more than one element
+        then this method will raise out with a RuntimeError.
+
     Parameters:
         circuit (:class:`qiskit.circuit.QuantumCircuit`): A Qiskit quantum circuit.
         backend_name (str): Backend name.
         passed_args (dict): Dictionary containing additional passed arguments, eg. shots.
 
+    Raises:
+        RuntimeError: If a multi-experiment circuit was provided.
+
     Returns:
         dict: A dict with IonQ API compatible values.
     """
+
+    if isinstance(circuit, (list, tuple)):
+        if len(circuit) > 1:
+            raise RuntimeError("Multi-experiment jobs are not supported!")
+        circuit = circuit[0]
+
     passed_args = passed_args or {}
     ionq_circ, _, meas_map = qiskit_circ_to_ionq_circ(circuit)
     creg_sizes, clbit_labels = get_register_sizes_and_labels(circuit.cregs)

test/helpers/test_gate_serialization.py

@@ -246,3 +246,27 @@ def test_circuit_with_multiple_registers():
     ]
     built, _, _ = qiskit_circ_to_ionq_circ(qc)
     assert built == expected
+
+
+def test_simple_circuit_wrapped_in_list():
+    """Test basic structure of a simple circuit when wrapped in a list."""
+    qc = QuantumCircuit(1, 1)
+    qc.h(0)
+    qc.measure(0, 0)
+    expected = [{"gate": "h", "targets": [0]}]
+    built, _, _ = qiskit_circ_to_ionq_circ([qc])
+    assert built == expected
+
+
+def test_multi_circuit_list():
+    """
+    Test that `qiskit_circ_to_ionq_circ` raises out if more than one circuit is provided.
+    """
+    qc0 = QuantumCircuit(1, 1)
+    qc0.measure(0, 0)
+    qc1 = QuantumCircuit(1, 1)
+    qc1.x(0)
+    qc1.measure(0, 0)
+    with pytest.raises(RuntimeError) as exc:
+        qiskit_circ_to_ionq_circ([qc0, qc1])
+    assert str(exc.value) == "Multi-experiment jobs are not supported!"

test/helpers/test_qiskit_to_ionq.py

@@ -28,6 +28,7 @@
 
 import json
 
+import pytest
 from qiskit import QuantumCircuit, QuantumRegister, ClassicalRegister
 
 from qiskit_ionq.helpers import qiskit_to_ionq, decompress_metadata_string_to_dict
@@ -101,6 +102,46 @@ def test_output_map__with_multiple_registers(simulator_backend):  # pylint: disa
     assert actual_output_map == [0, 1, 2, 3]
 
 
+def test_output_map__with_circuit_wrapped_in_list(
+    simulator_backend,
+):  # pylint: disable=invalid-name
+    """Test output mapping handles measurement correctly when input circuit is wrapped in a list
+
+    Args:
+        simulator_backend (IonQSimulatorBackend): A simulator backend fixture.
+    """
+    qc = QuantumCircuit(1, 1, name="test_name")
+    qc.measure(0, 0)
+    ionq_json = qiskit_to_ionq(
+        [qc], simulator_backend.name(), passed_args={"shots": 200, "sampler_seed": 42}
+    )
+    actual = json.loads(ionq_json)
+    actual_maps = actual.pop("registers") or {}
+    actual_output_map = actual_maps.pop("meas_mapped")
+
+    assert actual_output_map == [0]
+
+
+def test_output_map__with_multiple_circuits(simulator_backend):  # pylint: disable=invalid-name
+    """Test that `qiskit_to_ionq` raises out if more than one circuit is provided
+
+    Args:
+        simulator_backend (IonQSimulatorBackend): A simulator backend fixture.
+    """
+    qc0 = QuantumCircuit(1, 1, name="test_name_0")
+    qc0.measure(0, 0)
+
+    qc1 = QuantumCircuit(1, 1, name="test_name_1")
+    qc1.x(0)
+    qc1.measure(0, 0)
+
+    with pytest.raises(RuntimeError) as exc:
+        qiskit_to_ionq(
+            [qc0, qc1], simulator_backend.name(), passed_args={"shots": 123, "sampler_seed": 42}
+        )
+    assert str(exc.value) == "Multi-experiment jobs are not supported!"
+
+
 def test_metadata_header__with_multiple_registers(
     simulator_backend,
 ):  # pylint: disable=invalid-name