Add backwards comptability test for real amplitude circuits

Author: gadial

test/qpy_compat/test_qpy.py

@@ -918,6 +918,17 @@ def generate_v14_expr():
     ]
 
 
+def generate_real_amplitude_circuits():
+    """Real-amplitudes 2-local circuit`."""
+    from qiskit.circuit.library import RealAmplitudes
+    from qiskit import transpile
+
+    circuit = RealAmplitudes(num_qubits=2, reps=2)
+    isa_circuit = transpile(circuit.decompose(), optimization_level=0)
+
+    return [circuit, isa_circuit]
+
+
 def generate_box():
     """Circuits that contain `Box`.  Only added in Qiskit 2.0."""
     bare = QuantumCircuit(2, name="box-bare")
@@ -960,6 +971,8 @@ def generate_circuits(version_parts, current_version, load_context=False):
             generate_single_clbit_condition_teleportation(current_version)
         ]
 
+        output_circuits["real_amplitude.qpy"] = generate_real_amplitude_circuits()
+
     if version_parts >= (0, 19, 0):
         output_circuits["param_phase.qpy"] = generate_param_phase()
 
@@ -1109,8 +1122,14 @@ def load_qpy(qpy_files, version_parts):
             # See https://github.com/Qiskit/qiskit/pull/13814
             continue
         print(f"Loading qpy file: {path}")  # noqa: T201
-        with open(path, "rb") as fd:
-            qpy_circuits = load(fd)
+        try:
+            with open(path, "rb") as fd:
+                qpy_circuits = load(fd)
+        except Exception as ex:
+            msg = f"****QPY Load error****: Failed to load {path} with the exception: {ex}"
+            sys.stderr.write(msg)
+            sys.exit(1)
+
         equivalent = path in {"open_controlled_gates.qpy", "controlled_gates.qpy"}
         for i, circuit in enumerate(circuits):
             bind = None