Fix: Include cz in OpenQASM basis gates (#35)

qiskit_rigetti/_qcs_provider.py

@@ -122,7 +122,7 @@ def _configuration(name: str, num_qubits: int, local: bool, simulator: bool) ->
         backend_name=name,
         backend_version="",
         n_qubits=num_qubits,
-        basis_gates=["u1", "u2", "u3", "cx", "id"],
+        basis_gates=["u1", "u2", "u3", "cx", "id", "cz"],
         gates=[],
         local=local,
         simulator=simulator,

tests/test_qcs_backend.py

@@ -14,11 +14,13 @@
 #    limitations under the License.
 ##############################################################################
 import pytest
-from qiskit import execute, QuantumCircuit, QuantumRegister, ClassicalRegister
+from qiskit import execute, QuantumCircuit, QuantumRegister, ClassicalRegister, transpile
 from qiskit.providers import JobStatus
-from qiskit.circuit import Parameter
+from qiskit.circuit import Parameter, Qubit
+from qiskit.circuit.library import CZGate
 
-from qiskit_rigetti import RigettiQCSProvider, RigettiQCSBackend
+from qiskit_rigetti import RigettiQCSProvider, RigettiQCSBackend, QuilCircuit
+from qiskit_rigetti.gates import XYGate
 
 
 def test_run(backend: RigettiQCSBackend):
@@ -162,6 +164,26 @@ def test_run__backend_coupling_map():
     assert [(0, 1), (0, 2), (1, 0), (1, 2), (2, 0), (2, 1)] == sorted(backend.coupling_map.get_edges())
 
 
+def test_decomposition(backend: RigettiQCSBackend):
+    """Test that CZGate remains after the transpile."""
+    circuit = QuilCircuit(2, 2)
+    circuit.cz(0, 1)
+    circuit.measure_all()
+
+    circuit = transpile(circuit, backend=backend)
+    job = execute(circuit, backend, shots=1)
+    job.result()  # Just make sure nothing throws an exception so the circuit is valid
+
+    assert job.status() == JobStatus.DONE
+    assert len(circuit.data) == 4  # CZ, BARRIER, MEASURE, MEASURE
+    assert circuit.data[0] == (
+        CZGate(),
+        [Qubit(QuantumRegister(2, "q"), 0),
+         Qubit(QuantumRegister(2, "q"), 1)],
+        [],
+    )
+
+
 @pytest.fixture
 def backend():
     return RigettiQCSProvider().get_simulator(num_qubits=3)