Port regression test ticket 716 to Pytests

testsuite/pytests/sli2py_regressions/test_ticket_716.py

@@ -0,0 +1,54 @@
+# -*- coding: utf-8 -*-
+#
+# test_ticket_716.py
+#
+# This file is part of NEST.
+#
+# Copyright (C) 2004 The NEST Initiative
+#
+# NEST is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# NEST is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with NEST.  If not, see <http://www.gnu.org/licenses/>.
+
+import nest
+import pytest
+
+
+def test_stdp_dopamine_synapse_weight_constant_without_presynaptic_spikes():
+    """
+    Regression test for Ticket #716.
+
+    Ensure that the weight of an stdp_dopamine_synapse is constant in the absence of presynaptic spiking.
+    """
+    nest.ResetKernel()
+    vt = nest.Create("volume_transmitter")
+    nest.SetDefaults("stdp_dopamine_synapse", {"volume_transmitter": vt[0]})
+
+    n_pre = nest.Create("parrot_neuron")  # does not fire
+    n_post = nest.Create("parrot_neuron")
+    n_dopa = nest.Create("parrot_neuron")
+
+    sg_post = nest.Create("spike_generator", params={"spike_times": [0.5, 1.1, 3.4]})
+    sg_dopa = nest.Create("spike_generator", params={"spike_times": [1.4, 2.3, 4.6]})
+
+    nest.Connect(n_pre, n_post, syn_spec="stdp_dopamine_synapse")
+    nest.Connect(sg_dopa, n_dopa)
+    nest.Connect(n_dopa, vt)
+    nest.Connect(sg_post, n_post)
+
+    # Get initial weight
+    conns = nest.GetConnections(synapse_model="stdp_dopamine_synapse")
+    w0 = conns.get("weight")
+    nest.Simulate(10.0)
+    w1 = conns.get("weight")
+
+    assert abs(w0 - w1) <= 1e-13, f"Weight changed: w0={w0}, w1={w1}"