Improved test methods and coverage

test/python/test_sampler.py

@@ -1,9 +1,9 @@
 from __future__ import annotations
 
-import numpy as np
 import pytest
 from qiskit import QuantumCircuit
-from qiskit.circuit import Parameter
+from qiskit.circuit.library import RealAmplitudes
+from qiskit.primitives import SamplerResult
 
 from mqt.ddsim.sampler import Sampler
 
@@ -15,24 +15,104 @@ def sampler() -> Sampler:
 
 
 @pytest.fixture()
-def circuit() -> QuantumCircuit:
-    """The circuit fixture for the tests in this file."""
+def circuits() -> list[QuantumCircuit]:
+    """The circuit lists fixture for the tests in this file."""
 
-    theta_a = Parameter("theta_a")
-    theta_b = Parameter("theta_b")
-    qc = QuantumCircuit(1, name="test")
-    qc.rx(theta_a, 0)
-    qc.rz(theta_b, 0)
-    qc.rx(theta_a, 0)
-    qc.measure_all()
+    bell_1 = QuantumCircuit(2)
+    bell_1.h(0)
+    bell_1.cx(0, 1)
+    bell_1.measure_all()
 
-    return qc
+    bell_2 = QuantumCircuit(2)
+    bell_2.h(0)
+    bell_2.cx(0, 1)
+    bell_2.x(1)
+    bell_2.measure_all()
 
+    param_qc_1 = RealAmplitudes(num_qubits=2, reps=2)
+    param_qc_1.measure_all()
 
-def test_ddsim_sampler(circuit: QuantumCircuit, sampler: Sampler):
-    """Test DDSIM Sampler's functionality"""
-    job = sampler.run([circuit], [[np.pi / 2, np.pi]])
-    result = job.result()
-    counts = result.quasi_dists[0]
+    param_qc_2 = RealAmplitudes(num_qubits=2, reps=3)
+    param_qc_2.measure_all()
 
-    assert counts == {0: 1.0}
+    return [bell_1, bell_2, param_qc_1, param_qc_2]
+
+
+def compare_probs(prob: list[dict] | dict, target: list[dict] | dict):
+    if not isinstance(prob, list):
+        prob = [prob]
+    if not isinstance(target, list):
+        target = [target]
+
+    assert len(prob) == len(target)
+
+    for p, targ in zip(prob, target):
+        for key, t_val in targ.items():
+            if key in p:
+                assert abs(p[key] - t_val) < 0.1
+            else:
+                assert abs(t_val) < 0.1
+
+
+def test_sampler_run_single_circuit(circuits: list[QuantumCircuit], sampler: Sampler):
+    """Test Sampler.run() with single circuits"""
+    bell = circuits[0]
+    target = {0: 0.5, 3: 0.5, 1: 0, 2: 0}
+    target_binary = {"00": 0.5, "11": 0.5, "01": 0, "10": 0}
+    result = sampler.run([bell]).result()
+
+    assert isinstance(result, SamplerResult)
+    assert result.quasi_dists[0].shots == 1024
+
+    compare_probs(result.quasi_dists[0], target)
+    compare_probs(result.quasi_dists[0].binary_probabilities(), target_binary)
+
+
+def test_sample_run_multiple_circuits(circuits: list[QuantumCircuit], sampler: Sampler):
+    """Test Sampler.run() with multiple circuits."""
+    bell_1 = circuits[0]
+    bell_2 = circuits[1]
+    target = [{0: 0.5, 3: 0.5, 1: 0, 2: 0}, {1: 0.5, 2: 0.5, 3: 0, 0: 0}, {0: 0.5, 3: 0.5, 1: 0, 2: 0}]
+    result = sampler.run([bell_1, bell_2, bell_1]).result()
+    compare_probs(result.quasi_dists, target)
+
+
+def test_sampler_run_with_parameterized_circuits(circuits: list[QuantumCircuit], sampler: Sampler):
+    """Test Sampler.run() with parameterized circuits."""
+    param_qc = circuits[2]
+    parameter_values = [[0, 1, 1, 2, 3, 5], [1, 2, 3, 4, 5, 6]]
+    target = [
+        {"00": 0.1309248462975777, "01": 0.3608720796028448, "10": 0.09324865232050054, "11": 0.41495442177907715},
+        {"00": 0.06282290651933871, "01": 0.02877144385576705, "10": 0.606654494132085, "11": 0.3017511554928094},
+    ]
+    result = sampler.run([param_qc, param_qc], parameter_values).result()
+    compare_probs(result.quasi_dists[0].binary_probabilities(), target[0])
+    compare_probs(result.quasi_dists[1].binary_probabilities(), target[1])
+
+
+def test_sequential_run(circuits: list[QuantumCircuit], sampler: Sampler):
+    """Sampler stores the information about the circuits in an instance attribute.
+    If the same instance is used multiple times, the attribute still keeps the information about the circuits involved in previous runs.
+    This test ensures that if a circuit is analyzed in different runs, the information about this circuit is not saved twice.
+    """
+    qc_1 = circuits[2]
+    qc_2 = circuits[3]
+    parameter_values = [[0, 1, 1, 2, 3, 5], [1, 2, 3, 4, 5, 6], [0, 1, 2, 3, 4, 5, 6, 7]]
+    target = [
+        {"00": 0.1309248462975777, "01": 0.3608720796028448, "10": 0.09324865232050054, "11": 0.41495442177907715},
+        {"00": 0.06282290651933871, "01": 0.02877144385576705, "10": 0.606654494132085, "11": 0.3017511554928094},
+        {"00": 0.1880263994380416, "01": 0.6881971261189544, "10": 0.09326232720582443, "11": 0.030514147237179892},
+    ]
+
+    # First run
+    result = sampler.run(qc_1, parameter_values[0]).result()
+    compare_probs(result.quasi_dists[0].binary_probabilities(), target[0])
+    number_stored_circuits_first_run = len(sampler.circuits)
+
+    # Second run
+    result = sampler.run([qc_2, qc_1], [parameter_values[2], parameter_values[1]]).result()
+    compare_probs(result.quasi_dists[0].binary_probabilities(), target[2])
+    compare_probs(result.quasi_dists[1].binary_probabilities(), target[1])
+    number_stored_circuits_second_run = len(sampler.circuits)
+
+    assert number_stored_circuits_second_run == number_stored_circuits_first_run + 1