Deprecate fake backends based on BackendV1 (backport #12660)

qiskit/providers/fake_provider/fake_backend.py

@@ -23,7 +23,7 @@
 from qiskit.providers import BackendV1
 from qiskit import pulse
 from qiskit.exceptions import QiskitError
-from qiskit.utils import optionals as _optionals
+from qiskit.utils import optionals as _optionals, deprecate_func
 from qiskit.providers import basic_provider
 
 
@@ -39,6 +39,13 @@ def __init__(self, token="123456", url="https://"):
 class FakeBackend(BackendV1):
     """This is a dummy backend just for testing purposes."""
 
+    @deprecate_func(
+        since="1.2",
+        removal_timeline="in the 2.0 release",
+        additional_msg="Fake backends using BackendV1 are deprecated in favor of "
+        ":class:`.GenericBackendV2`. You can convert BackendV1 to "
+        ":class:`.BackendV2` with :class:`.BackendV2Converter`.",
+    )
     def __init__(self, configuration, time_alive=10):
         """FakeBackend initializer.
 

qiskit/providers/fake_provider/generic_backend_v2.py

@@ -567,18 +567,12 @@ def _setup_sim(self) -> None:
 
     @classmethod
     def _default_options(cls) -> Options:
-        with warnings.catch_warnings():  # TODO remove catch once aer release without Provider ABC
-            warnings.filterwarnings(
-                "ignore",
-                category=DeprecationWarning,
-                message=".+abstract Provider and ProviderV1.+",
-            )
-            if _optionals.HAS_AER:
-                from qiskit_aer import AerSimulator
+        if _optionals.HAS_AER:
+            from qiskit_aer import AerSimulator
 
-                return AerSimulator._default_options()
-            else:
-                return BasicSimulator._default_options()
+            return AerSimulator._default_options()
+        else:
+            return BasicSimulator._default_options()
 
     def drive_channel(self, qubit: int):
         drive_channels_map = getattr(self, "channels_map", {}).get("drive", {})

qiskit/visualization/circuit/_utils.py

@@ -387,7 +387,7 @@ def _get_valid_justify_arg(justify):
         warn(
             f"Setting QuantumCircuit.draw()’s or circuit_drawer()'s justify argument: {justify}, to a "
             "value other than 'left', 'right', 'none' or None (='left'). Default 'left' will be used. "
-            "Support for invalid justify arguments is deprecated as of qiskit 1.2.0. Starting no "
+            "Support for invalid justify arguments is deprecated as of Qiskit 1.2.0. Starting no "
             "earlier than 3 months after the release date, invalid arguments will error.",
             DeprecationWarning,
             2,

test/python/circuit/test_parameters.py

@@ -31,10 +31,11 @@
 from qiskit.compiler import assemble, transpile
 from qiskit import pulse
 from qiskit.quantum_info import Operator
-from qiskit.providers.fake_provider import Fake5QV1
+from qiskit.providers.fake_provider import Fake5QV1, GenericBackendV2
 from qiskit.providers.basic_provider import BasicSimulator
 from qiskit.utils import parallel_map
 from test import QiskitTestCase, combine  # pylint: disable=wrong-import-order
+from ..legacy_cmaps import BOGOTA_CMAP
 
 
 def raise_if_parameter_table_invalid(circuit):
@@ -1074,6 +1075,26 @@ def test_transpiling_multiple_parameterized_circuits(self):
 
         self.assertTrue(len(job.result().results), 2)
 
+    @data(0, 1, 2, 3)
+    def test_transpile_across_optimization_levelsV1(self, opt_level):
+        """Verify parameterized circuits can be transpiled with all default pass managers.
+        To remove once Fake5QV1 gets removed"""
+
+        qc = QuantumCircuit(5, 5)
+
+        theta = Parameter("theta")
+        phi = Parameter("phi")
+
+        qc.rx(theta, 0)
+        qc.x(0)
+        for i in range(5 - 1):
+            qc.rxx(phi, i, i + 1)
+
+        qc.measure(range(5 - 1), range(5 - 1))
+        with self.assertWarns(DeprecationWarning):
+            backend = Fake5QV1()
+        transpile(qc, backend, optimization_level=opt_level)
+
     @data(0, 1, 2, 3)
     def test_transpile_across_optimization_levels(self, opt_level):
         """Verify parameterized circuits can be transpiled with all default pass managers."""
@@ -1090,7 +1111,15 @@ def test_transpile_across_optimization_levels(self, opt_level):
 
         qc.measure(range(5 - 1), range(5 - 1))
 
-        transpile(qc, Fake5QV1(), optimization_level=opt_level)
+        transpile(
+            qc,
+            GenericBackendV2(
+                num_qubits=5,
+                coupling_map=BOGOTA_CMAP,
+                seed=42,
+            ),
+            optimization_level=opt_level,
+        )
 
     def test_repeated_gates_to_dag_and_back(self):
         """Verify circuits with repeated parameterized gates can be converted

test/python/circuit/test_scheduled_circuit.py

@@ -33,8 +33,9 @@ class TestScheduledCircuit(QiskitTestCase):
 
     def setUp(self):
         super().setUp()
-        self.backend_with_dt = Fake27QPulseV1()
-        self.backend_without_dt = Fake27QPulseV1()
+        with self.assertWarns(DeprecationWarning):
+            self.backend_with_dt = Fake27QPulseV1()
+            self.backend_without_dt = Fake27QPulseV1()
         delattr(self.backend_without_dt.configuration(), "dt")
         # Remove timing constraints from the backends (alignment values,
         # granularity and min_length), so that these values will default
@@ -50,21 +51,24 @@ def setUp(self):
     def test_schedule_circuit_when_backend_tells_dt(self):
         """dt is known to transpiler by backend"""
         qc = QuantumCircuit(2)
-        qc.delay(0.1, 0, unit="ms")  # 450000[dt]
+        qc.delay(0.1, 0, unit="ms")  # 450450[dt]
         qc.delay(100, 0, unit="ns")  # 450[dt]
-        qc.h(0)  # 160[dt]
-        qc.h(1)  # 160[dt]
-        sc = transpile(qc, self.backend_with_dt, scheduling_method="alap", layout_method="trivial")
-        self.assertEqual(sc.duration, 450546)
+        qc.h(0)  # 195[dt]
+        qc.h(1)  # 210[dt]
+
+        backend = GenericBackendV2(2, calibrate_instructions=True, seed=42)
+
+        sc = transpile(qc, backend, scheduling_method="alap", layout_method="trivial")
+        self.assertEqual(sc.duration, 451095)
         self.assertEqual(sc.unit, "dt")
         self.assertEqual(sc.data[0].operation.name, "delay")
-        self.assertEqual(sc.data[0].operation.duration, 450450)
+        self.assertEqual(sc.data[0].operation.duration, 450900)
         self.assertEqual(sc.data[0].operation.unit, "dt")
         self.assertEqual(sc.data[1].operation.name, "rz")
         self.assertEqual(sc.data[1].operation.duration, 0)
         self.assertEqual(sc.data[1].operation.unit, "dt")
         self.assertEqual(sc.data[4].operation.name, "delay")
-        self.assertEqual(sc.data[4].operation.duration, 450450)
+        self.assertEqual(sc.data[4].operation.duration, 450885)
         self.assertEqual(sc.data[4].operation.unit, "dt")
 
     def test_schedule_circuit_when_transpile_option_tells_dt(self):
@@ -301,7 +305,7 @@ def test_convert_duration_to_dt(self):
         """Test that circuit duration unit conversion is applied only when necessary.
         Tests fix for bug reported in PR #11782."""
 
-        backend = GenericBackendV2(num_qubits=3, calibrate_instructions=True, seed=10)
+        backend = GenericBackendV2(num_qubits=3, calibrate_instructions=True, seed=42)
         schedule_config = ScheduleConfig(
             inst_map=backend.target.instruction_schedule_map(),
             meas_map=backend.meas_map,

test/python/compiler/test_assembler.py

@@ -63,7 +63,8 @@ def setUp(self):
         self.circ.cx(qr[0], qr[1])
         self.circ.measure(qr, cr)
 
-        self.backend = Fake5QV1()
+        with self.assertWarns(DeprecationWarning):
+            self.backend = Fake5QV1()
         self.backend_config = self.backend.configuration()
         self.num_qubits = self.backend_config.n_qubits
 
@@ -591,7 +592,8 @@ def test_pulse_gates_with_parameteric_pulses(self):
         circ.h(0)
         circ.add_calibration("h", [0], custom_h_schedule)
 
-        backend = FakeOpenPulse2Q()
+        with self.assertWarns(DeprecationWarning):
+            backend = FakeOpenPulse2Q()
         backend.configuration().parametric_pulses = ["drag"]
         with self.assertWarns(DeprecationWarning):
             qobj = assemble(circ, backend)
@@ -974,7 +976,8 @@ class TestPulseAssembler(QiskitTestCase):
 
     def setUp(self):
         super().setUp()
-        self.backend = FakeOpenPulse2Q()
+        with self.assertWarns(DeprecationWarning):
+            self.backend = FakeOpenPulse2Q()
         self.backend_config = self.backend.configuration()
 
         test_pulse = pulse.Waveform(
@@ -1282,7 +1285,8 @@ def test_pulse_name_conflicts(self):
 
     def test_pulse_name_conflicts_in_other_schedule(self):
         """Test two pulses with the same name in different schedule can be resolved."""
-        backend = Fake27QPulseV1()
+        with self.assertWarns(DeprecationWarning):
+            backend = Fake27QPulseV1()
         defaults = backend.defaults()
 
         schedules = []
@@ -1390,7 +1394,8 @@ def test_assemble_parametric(self):
             )
             << sched.duration
         )
-        backend = FakeOpenPulse3Q()
+        with self.assertWarns(DeprecationWarning):
+            backend = FakeOpenPulse3Q()
         backend.configuration().parametric_pulses = [
             "gaussian",
             "drag",
@@ -1437,7 +1442,8 @@ def test_assemble_parametric_unsupported(self):
         )
         sched += Play(pulse.Constant(duration=25, amp=1), DriveChannel(2))
 
-        backend = FakeOpenPulse3Q()
+        with self.assertWarns(DeprecationWarning):
+            backend = FakeOpenPulse3Q()
         backend.configuration().parametric_pulses = ["something_extra"]
 
         with self.assertWarns(DeprecationWarning):
@@ -1449,7 +1455,8 @@ def test_assemble_parametric_unsupported(self):
 
     def test_assemble_parametric_pulse_kwarg_with_backend_setting(self):
         """Test that parametric pulses respect the kwarg over backend"""
-        backend = Fake27QPulseV1()
+        with self.assertWarns(DeprecationWarning):
+            backend = Fake27QPulseV1()
 
         qc = QuantumCircuit(1, 1)
         qc.x(0)
@@ -1465,7 +1472,8 @@ def test_assemble_parametric_pulse_kwarg_with_backend_setting(self):
 
     def test_assemble_parametric_pulse_kwarg_empty_list_with_backend_setting(self):
         """Test that parametric pulses respect the kwarg as empty list over backend"""
-        backend = Fake27QPulseV1()
+        with self.assertWarns(DeprecationWarning):
+            backend = Fake27QPulseV1()
 
         qc = QuantumCircuit(1, 1)
         qc.x(0)
@@ -1822,7 +1830,8 @@ def setUp(self):
         super().setUp()
         self.schedule = pulse.Schedule(name="fake_experiment")
 
-        self.backend = FakeOpenPulse2Q()
+        with self.assertWarns(DeprecationWarning):
+            self.backend = FakeOpenPulse2Q()
         self.config = self.backend.configuration()
         self.defaults = self.backend.defaults()
         self.qubit_lo_freq = list(self.defaults.qubit_freq_est)
@@ -1963,7 +1972,8 @@ def test_missing_lo_ranges(self):
 
     def test_unsupported_meas_level(self):
         """Test that assembly raises an error if meas_level is not supported"""
-        backend = FakeOpenPulse2Q()
+        with self.assertWarns(DeprecationWarning):
+            backend = FakeOpenPulse2Q()
         backend.configuration().meas_levels = [1, 2]
         with self.assertRaises(QiskitError), self.assertWarns(DeprecationWarning):
             assemble(
@@ -1983,7 +1993,8 @@ def test_unsupported_meas_level(self):
 
     def test_single_and_deprecated_acquire_styles(self):
         """Test that acquires are identically combined with Acquires that take a single channel."""
-        backend = FakeOpenPulse2Q()
+        with self.assertWarns(DeprecationWarning):
+            backend = FakeOpenPulse2Q()
         new_style_schedule = Schedule()
         acq_dur = 1200
         for i in range(2):

test/python/compiler/test_compiler.py

@@ -188,7 +188,6 @@ def test_example_swap_bits(self):
 
     def test_parallel_compile(self):
         """Trigger parallel routines in compile."""
-        backend = Fake20QV1()
         qr = QuantumRegister(16)
         cr = ClassicalRegister(2)
         qc = QuantumCircuit(qr, cr)
@@ -198,6 +197,7 @@ def test_parallel_compile(self):
         qc.measure(qr[5], cr[0])
         qlist = [qc for k in range(10)]
         with self.assertWarns(DeprecationWarning):
+            backend = Fake20QV1()
             qobj = assemble(transpile(qlist, backend=backend))
         self.assertEqual(len(qobj.experiments), 10)
 
@@ -500,7 +500,8 @@ def test_yzy_zyz_cases(self):
 
         See: https://github.com/Qiskit/qiskit-terra/issues/607
         """
-        backend = Fake5QV1()
+        with self.assertWarns(DeprecationWarning):
+            backend = Fake5QV1()
         qr = QuantumRegister(2)
         circ1 = QuantumCircuit(qr)
         circ1.cx(qr[0], qr[1])

test/python/compiler/test_disassembler.py

@@ -457,7 +457,8 @@ class TestPulseScheduleDisassembler(QiskitTestCase):
 
     def setUp(self):
         super().setUp()
-        self.backend = FakeOpenPulse2Q()
+        with self.assertWarns(DeprecationWarning):
+            self.backend = FakeOpenPulse2Q()
         self.backend_config = self.backend.configuration()
         self.backend_config.parametric_pulses = ["constant", "gaussian", "gaussian_square", "drag"]
 

test/python/compiler/test_scheduler.py

@@ -15,7 +15,7 @@
 from qiskit.circuit import QuantumRegister, ClassicalRegister, QuantumCircuit
 from qiskit.exceptions import QiskitError
 from qiskit.pulse import InstructionScheduleMap, Schedule
-from qiskit.providers.fake_provider import FakeOpenPulse3Q
+from qiskit.providers.fake_provider import FakeOpenPulse3Q, GenericBackendV2
 from qiskit.compiler.scheduler import schedule
 from test import QiskitTestCase  # pylint: disable=wrong-import-order
 
@@ -37,9 +37,9 @@ def setUp(self):
         self.circ2.cx(qr2[0], qr2[1])
         self.circ2.measure(qr2, cr2)
 
-        self.backend = FakeOpenPulse3Q()
-        self.backend_config = self.backend.configuration()
-        self.num_qubits = self.backend_config.n_qubits
+        self.backend = GenericBackendV2(
+            3, calibrate_instructions=True, basis_gates=["cx", "u1", "u2", "u3"], seed=42
+        )
 
     def test_instruction_map_and_backend_not_supplied(self):
         """Test instruction map and backend not supplied."""
@@ -51,6 +51,8 @@ def test_instruction_map_and_backend_not_supplied(self):
 
     def test_instruction_map_and_backend_defaults_unavailable(self):
         """Test backend defaults unavailable when backend is provided, but instruction map is not."""
+        with self.assertWarns(DeprecationWarning):
+            self.backend = FakeOpenPulse3Q()
         self.backend._defaults = None
         with self.assertRaisesRegex(
             QiskitError, r"The backend defaults are unavailable. The backend may not support pulse."

test/python/compiler/test_sequencer.py

@@ -13,6 +13,8 @@
 # pylint: disable=missing-function-docstring
 
 """Tests basic functionality of the sequence function"""
+# TODO with the removal of pulses, this file can be removed too.
+
 import unittest
 
 from qiskit import QuantumCircuit, pulse
@@ -27,7 +29,8 @@ class TestSequence(QiskitTestCase):
 
     def setUp(self):
         super().setUp()
-        self.backend = Fake127QPulseV1()
+        with self.assertWarns(DeprecationWarning):
+            self.backend = Fake127QPulseV1()
         self.backend.configuration().timing_constraints = {}
 
     def test_sequence_empty(self):