Remove Sampler.close, assert DeprecationWarning of opflow, and update…

… dependency (Qiskit#1804)

Since qiskit-terra 0.24, `Sampler` does not have `close()` but Aer's `Sampler` still have the method. This commit takes the method as well as upgrade of Python versions in tutorial tests from 3.7 to 3.8.

* rm close
* assert DeprecationWarning
* update dependency

.github/workflows/docs.yml

@@ -50,7 +50,7 @@ jobs:
     needs: [docs]
     strategy:
       matrix:
-        python-version: [3.7]
+        python-version: [3.8]
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python ${{ matrix.python-version }}

qiskit_aer/primitives/sampler.py

@@ -66,7 +66,6 @@ def __init__(
             skip_transpilation: if True, transpilation is skipped.
         """
         super().__init__(options=run_options)
-        self._is_closed = False
         self._backend = AerSimulator()
         backend_options = {} if backend_options is None else backend_options
         self._backend.set_options(**backend_options)
@@ -82,9 +81,6 @@ def _call(
         parameter_values: Sequence[Sequence[float]],
         **run_options,
     ) -> SamplerResult:
-        if self._is_closed:
-            raise QiskitError("The primitive has been closed.")
-
         seed = run_options.pop("seed", None)
         if seed is not None:
             run_options.setdefault("seed_simulator", seed)
@@ -158,9 +154,6 @@ def _run(
         job.submit()
         return job
 
-    def close(self):
-        self._is_closed = True
-
     @staticmethod
     def _preprocess_circuit(circuit: QuantumCircuit):
         circuit = init_circuit(circuit)

test/terra/primitives/test_estimator.py

@@ -53,15 +53,16 @@ def setUp(self):
     def test_estimator(self, abelian_grouping):
         """test for a simple use case"""
         lst = [("XX", 1), ("YY", 2), ("ZZ", 3)]
-        with self.subTest("PauliSumOp"):
-            observable = PauliSumOp.from_list(lst)
-            ansatz = RealAmplitudes(num_qubits=2, reps=2)
-            est = Estimator(abelian_grouping=abelian_grouping)
-            result = est.run(
-                ansatz, observable, parameter_values=[[0, 1, 1, 2, 3, 5]], seed=15
-            ).result()
-            self.assertIsInstance(result, EstimatorResult)
-            np.testing.assert_allclose(result.values, [1.728515625])
+        with self.assertWarns(DeprecationWarning):
+            with self.subTest("PauliSumOp"):
+                observable = PauliSumOp.from_list(lst)
+                ansatz = RealAmplitudes(num_qubits=2, reps=2)
+                est = Estimator(abelian_grouping=abelian_grouping)
+                result = est.run(
+                    ansatz, observable, parameter_values=[[0, 1, 1, 2, 3, 5]], seed=15
+                ).result()
+                self.assertIsInstance(result, EstimatorResult)
+                np.testing.assert_allclose(result.values, [1.728515625])
 
         with self.subTest("SparsePauliOp"):
             observable = SparsePauliOp.from_list(lst)