Uncertainty models using circuits (qiskit-community/qiskit-aqua#908)

* make variational UMs accept circuits

* test circuit variants

* add deprecation warnings if varform is passed

* fix typo Uni -> Multi

* fix warning filters

* filter deprecation warnings on univ. var. dist

* only filter warnings locally

test/finance/test_data_providers.py

@@ -37,7 +37,7 @@ def setUp(self):
 
     def tearDown(self):
         super().tearDown()
-        warnings.filterwarnings(action="ignore", message="unclosed", category=ResourceWarning)
+        warnings.filterwarnings(action="always", message="unclosed", category=ResourceWarning)
 
     def test_wrong_use(self):
         """ wrong use test """

test/finance/test_european_call_expected_value.py

@@ -15,10 +15,13 @@
 """ Test European Call Expected Value uncertainty problem """
 
 from test.finance import QiskitFinanceTestCase
+import warnings
+from ddt import ddt, data
 
 import numpy as np
 
 from qiskit import BasicAer
+from qiskit.circuit import ParameterVector
 from qiskit.aqua import aqua_globals, QuantumInstance
 from qiskit.aqua.algorithms import AmplitudeEstimation
 from qiskit.aqua.components.initial_states import Custom
@@ -28,6 +31,7 @@
 from qiskit.finance.components.uncertainty_problems import EuropeanCallExpectedValue
 
 
+@ddt
 class TestEuropeanCallExpectedValue(QiskitFinanceTestCase):
     """Tests European Call Expected Value uncertainty problem """
 
@@ -36,8 +40,18 @@ def setUp(self):
         self.seed = 457
         aqua_globals.random_seed = self.seed
 
-    def test_ecev(self):
+    def tearDown(self):
+        super().tearDown()
+        warnings.filterwarnings(action="always", category=DeprecationWarning)
+
+    @data(False, True)
+    def test_ecev(self, use_circuits):
         """ European Call Expected Value test """
+        if not use_circuits:
+            # ignore deprecation warnings from the deprecation of VariationalForm as input for
+            # the univariate variational distribution
+            warnings.filterwarnings("ignore", category=DeprecationWarning)
+
         bounds = np.array([0., 7.])
         num_qubits = [3]
         entangler_map = []
@@ -54,10 +68,17 @@ def test_ecev(self):
         var_form = RY(int(np.sum(num_qubits)), depth=1,
                       initial_state=init_distribution,
                       entangler_map=entangler_map, entanglement_gate='cz')
+        if use_circuits:
+            theta = ParameterVector('θ', var_form.num_parameters)
+            var_form = var_form.construct_circuit(theta)
+
         uncertainty_model = UnivariateVariationalDistribution(
             int(sum(num_qubits)), var_form, g_params,
             low=bounds[0], high=bounds[1])
 
+        if use_circuits:
+            uncertainty_model._var_form_params = theta
+
         strike_price = 2
         c_approx = 0.25
         european_call = EuropeanCallExpectedValue(uncertainty_model,
@@ -71,3 +92,6 @@ def test_ecev(self):
         result = algo.run(quantum_instance=BasicAer.get_backend('statevector_simulator'))
         self.assertAlmostEqual(result['estimation'], 1.2580, places=4)
         self.assertAlmostEqual(result['max_probability'], 0.8785, places=4)
+
+        if not use_circuits:
+            warnings.filterwarnings(action="always", category=DeprecationWarning)