🐍 Update some of the Python configuration (#280)

This PR adds a proper pytest and coverage configuration and also some
further `ruff` checks and corresponding auto-fixes.

---------

Signed-off-by: burgholzer <burgholzer@me.com>
Co-authored-by: Stefan Hillmich <stefan.hillmich@scch.at>
Co-authored-by: Stefan Hillmich <hillmich@users.noreply.github.com>

mqt/ddsim/__init__.py

@@ -1,4 +1,5 @@
-from mqt.ddsim.pyddsim import (  # noqa: I001
+from __future__ import annotations  # noqa: I001
+from mqt.ddsim.pyddsim import (
     CircuitSimulator,
     ConstructionMode,
     HybridCircuitSimulator,

mqt/ddsim/error.py

@@ -1,13 +1,12 @@
-"""
-Exception for errors raised by DDSIM simulator.
-"""
+"""Exception for errors raised by DDSIM simulator."""
+from __future__ import annotations
 
 from qiskit import QiskitError
 
 
 class DDSIMError(QiskitError):
     """Class for errors raised by the DDSIM simulator."""
 
-    def __init__(self, *message):
+    def __init__(self, *message) -> None:
         """Set the error message."""
         super().__init__(*message)

mqt/ddsim/hybridqasmsimulator.py

@@ -1,11 +1,11 @@
 """Backend for DDSIM Hybrid Schrodinger-Feynman Simulator."""
+from __future__ import annotations
 
 import logging
 import time
 import uuid
 import warnings
 from math import log2
-from typing import List, Union
 
 from qiskit import QiskitError, QuantumCircuit
 from qiskit.compiler import assemble
@@ -23,7 +23,7 @@
 
 
 class HybridQasmSimulatorBackend(BackendV1):
-    """Python interface to MQT DDSIM Hybrid Schrodinger-Feynman Simulator"""
+    """Python interface to MQT DDSIM Hybrid Schrodinger-Feynman Simulator."""
 
     SHOW_STATE_VECTOR = False
 
@@ -37,7 +37,7 @@ def _default_options(cls) -> Options:
             nthreads=local_hardware_info()["cpus"],
         )
 
-    def __init__(self, configuration=None, provider=None):
+    def __init__(self, configuration=None, provider=None) -> None:
         conf = {
             "backend_name": "hybrid_qasm_simulator",
             "backend_version": __version__,
@@ -90,7 +90,7 @@ def __init__(self, configuration=None, provider=None):
         }
         super().__init__(configuration=configuration or BackendConfiguration.from_dict(conf), provider=provider)
 
-    def run(self, quantum_circuits: Union[QuantumCircuit, List[QuantumCircuit]], **options):
+    def run(self, quantum_circuits: QuantumCircuit | list[QuantumCircuit], **options):
         if isinstance(quantum_circuits, (QasmQobj, PulseQobj)):
             msg = "QasmQobj and PulseQobj are not supported."
             raise QiskitError(msg)
@@ -189,6 +189,7 @@ def _validate(self, _quantum_circuit):
 
     def status(self):
         """Return backend status.
+
         Returns:
             BackendStatus: the status of the backend.
         """

mqt/ddsim/hybridstatevectorsimulator.py

@@ -1,4 +1,5 @@
 """Backend for DDSIM Hybrid Schrodinger-Feynman Simulator."""
+from __future__ import annotations
 
 import logging
 from math import log2
@@ -13,11 +14,11 @@
 
 
 class HybridStatevectorSimulatorBackend(HybridQasmSimulatorBackend):
-    """Python interface to MQT DDSIM Hybrid Schrodinger-Feynman Simulator"""
+    """Python interface to MQT DDSIM Hybrid Schrodinger-Feynman Simulator."""
 
     SHOW_STATE_VECTOR = True
 
-    def __init__(self, configuration=None, provider=None):
+    def __init__(self, configuration=None, provider=None) -> None:
         conf = {
             "backend_name": "hybrid_statevector_simulator",
             "backend_version": __version__,

mqt/ddsim/job.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import functools
 import logging
 from concurrent import futures
@@ -8,12 +10,12 @@
 
 
 def requires_submit(func):
-    """
-    Decorator to ensure that a submit has been performed before
+    """Decorator to ensure that a submit has been performed before
     calling the method.
 
     Args:
         func (callable): test function to be decorated.
+
     Returns:
         callable: the decorated function.
     """
@@ -37,7 +39,7 @@ class DDSIMJob(JobV1):
 
     _executor = futures.ThreadPoolExecutor(max_workers=1)
 
-    def __init__(self, backend, job_id, fn, qobj_experiment, **args):
+    def __init__(self, backend, job_id, fn, qobj_experiment, **args) -> None:
         super().__init__(backend, job_id)
         self._fn = fn
         self.qobj_experiment = qobj_experiment
@@ -63,10 +65,11 @@ def result(self, timeout=None):
         # pylint: disable=arguments-differ
         """Get job result. The behavior is the same as the underlying
         concurrent Future objects,
-        https://docs.python.org/3/library/concurrent.futures.html#future-objects
+        https://docs.python.org/3/library/concurrent.futures.html#future-objects.
 
         Args:
             timeout (float): number of seconds to wait for results.
+
         Returns:
             qiskit.Result: Result object
         Raises:
@@ -81,7 +84,7 @@ def cancel(self):
 
     @requires_submit
     def status(self) -> JobStatus:
-        """Gets the status of the job by querying the Python's future
+        """Gets the status of the job by querying the Python's future.
 
         Returns:
             JobStatus: The current JobStatus

mqt/ddsim/pathqasmsimulator.py

@@ -1,11 +1,11 @@
 """Backend for DDSIM Task-Based Simulator."""
+from __future__ import annotations
 
 import logging
 import pathlib
 import time
 import uuid
 import warnings
-from typing import List, Union
 
 from qiskit import QiskitError, QuantumCircuit
 from qiskit.compiler import assemble
@@ -109,7 +109,7 @@ def get_simulation_path(
 
 
 class PathQasmSimulatorBackend(BackendV1):
-    """Python interface to MQT DDSIM Simulation Path Framework"""
+    """Python interface to MQT DDSIM Simulation Path Framework."""
 
     SHOW_STATE_VECTOR = False
 
@@ -131,7 +131,7 @@ def _default_options(cls) -> Options:
             cotengra_dump_path=True,
         )
 
-    def __init__(self, configuration=None, provider=None):
+    def __init__(self, configuration=None, provider=None) -> None:
         conf = {
             "backend_name": "path_sim_qasm_simulator",
             "backend_version": __version__,
@@ -203,7 +203,7 @@ def __init__(self, configuration=None, provider=None):
         }
         super().__init__(configuration=configuration or BackendConfiguration.from_dict(conf), provider=provider)
 
-    def run(self, quantum_circuits: Union[QuantumCircuit, List[QuantumCircuit]], **options):
+    def run(self, quantum_circuits: QuantumCircuit | list[QuantumCircuit], **options):
         if isinstance(quantum_circuits, (QasmQobj, PulseQobj)):
             msg = "QasmQobj and PulseQobj are not supported."
             raise QiskitError(msg)
@@ -310,6 +310,7 @@ def _validate(self, _quantum_circuit):
 
     def status(self):
         """Return backend status.
+
         Returns:
             BackendStatus: the status of the backend.
         """

mqt/ddsim/pathstatevectorsimulator.py

@@ -1,4 +1,5 @@
 """Backend for DDSIM."""
+from __future__ import annotations
 
 import logging
 
@@ -11,11 +12,11 @@
 
 
 class PathStatevectorSimulatorBackend(PathQasmSimulatorBackend):
-    """Python interface to MQT DDSIM Simulation Path Framework"""
+    """Python interface to MQT DDSIM Simulation Path Framework."""
 
     SHOW_STATE_VECTOR = True
 
-    def __init__(self, configuration=None, provider=None):
+    def __init__(self, configuration=None, provider=None) -> None:
         conf = {
             "backend_name": "path_sim_statevector_simulator",
             "backend_version": __version__,

mqt/ddsim/provider.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from qiskit.providers import ProviderV1
 from qiskit.providers.providerutils import filter_backends
 
@@ -13,7 +15,7 @@
 class DDSIMProvider(ProviderV1):
     _BACKENDS = None
 
-    def __init__(self):
+    def __init__(self) -> None:
         if DDSIMProvider._BACKENDS is None:
             DDSIMProvider._BACKENDS = [
                 ("qasm_simulator", QasmSimulatorBackend, None, None),
@@ -43,5 +45,5 @@ def backends(self, name=None, filters=None, **kwargs):
                 backends.append(backend_cls(**opts))
         return filter_backends(backends, filters=filters, **kwargs)
 
-    def __str__(self):
+    def __str__(self) -> str:
         return "DDSIMProvider"

mqt/ddsim/qasmsimulator.py

@@ -1,10 +1,10 @@
 """Backend for DDSIM."""
+from __future__ import annotations
 
 import logging
 import time
 import uuid
 import warnings
-from typing import Dict, List, Union
 
 from qiskit import QiskitError, QuantumCircuit
 from qiskit.compiler import assemble
@@ -20,7 +20,7 @@
 
 
 class QasmSimulatorBackend(BackendV1):
-    """Python interface to MQT DDSIM"""
+    """Python interface to MQT DDSIM."""
 
     SHOW_STATE_VECTOR = False
 
@@ -35,7 +35,7 @@ def _default_options(cls) -> Options:
             approximation_strategy="fidelity",
         )
 
-    def __init__(self, configuration=None, provider=None):
+    def __init__(self, configuration=None, provider=None) -> None:
         conf = {
             "backend_name": "qasm_simulator",
             "backend_version": __version__,
@@ -106,7 +106,7 @@ def __init__(self, configuration=None, provider=None):
         }
         super().__init__(configuration=configuration or BackendConfiguration.from_dict(conf), provider=provider)
 
-    def run(self, quantum_circuits: Union[QuantumCircuit, List[QuantumCircuit]], **options) -> DDSIMJob:
+    def run(self, quantum_circuits: QuantumCircuit | list[QuantumCircuit], **options) -> DDSIMJob:
         if isinstance(quantum_circuits, (QasmQobj, PulseQobj)):
             msg = "QasmQobj and PulseQobj are not supported."
             raise QiskitError(msg)
@@ -147,7 +147,7 @@ def _run_job(self, job_id, qobj_instance: Qobj, **options) -> Result:
         }
         return Result.from_dict(result)
 
-    def run_experiment(self, qobj_experiment: QasmQobjExperiment, **options) -> Dict:
+    def run_experiment(self, qobj_experiment: QasmQobjExperiment, **options) -> dict:
         start_time = time.time()
         approximation_step_fidelity = options.get("approximation_step_fidelity", 1.0)
         approximation_steps = options.get("approximation_steps", 1)
@@ -184,6 +184,7 @@ def _validate(self, _quantum_circuit):
 
     def status(self) -> BackendStatus:
         """Return backend status.
+
         Returns:
             BackendStatus: the status of the backend.
         """

mqt/ddsim/statevectorsimulator.py

@@ -1,4 +1,5 @@
 """Backend for DDSIM."""
+from __future__ import annotations
 
 import logging
 
@@ -11,11 +12,11 @@
 
 
 class StatevectorSimulatorBackend(QasmSimulatorBackend):
-    """Python interface to MQT DDSIM"""
+    """Python interface to MQT DDSIM."""
 
     SHOW_STATE_VECTOR = True
 
-    def __init__(self, configuration=None, provider=None):
+    def __init__(self, configuration=None, provider=None) -> None:
         conf = {
             "backend_name": "statevector_simulator",
             "backend_version": __version__,

mqt/ddsim/unitarysimulator.py

@@ -1,11 +1,11 @@
 """Backend for DDSIM Unitary Simulator."""
+from __future__ import annotations
 
 import logging
 import time
 import uuid
 import warnings
 from math import log2, sqrt
-from typing import List, Union
 
 import numpy as np
 from qiskit import QiskitError, QuantumCircuit
@@ -26,7 +26,7 @@
 class UnitarySimulatorBackend(BackendV1):
     """Decision diagram-based unitary simulator."""
 
-    def __init__(self, configuration=None, provider=None, **fields):
+    def __init__(self, configuration=None, provider=None, **fields) -> None:
         conf = {
             "backend_name": "unitary_simulator",
             "backend_version": __version__,
@@ -102,7 +102,7 @@ def __init__(self, configuration=None, provider=None, **fields):
     def _default_options(cls):
         return Options(shots=1, mode="recursive", parameter_binds=None)
 
-    def run(self, quantum_circuits: Union[QuantumCircuit, List[QuantumCircuit]], **options):
+    def run(self, quantum_circuits: QuantumCircuit | list[QuantumCircuit], **options):
         if isinstance(quantum_circuits, (QasmQobj, PulseQobj)):
             msg = "QasmQobj and PulseQobj are not supported."
             raise QiskitError(msg)
@@ -185,7 +185,7 @@ def _validate(self, qobj):
         """Semantic validations of the qobj which cannot be done via schemas.
         Some of these may later move to backend schemas.
         1. No shots
-        2. No measurements in the middle
+        2. No measurements in the middle.
         """
         n_qubits = qobj.config.n_qubits
         max_qubits = self.configuration().n_qubits