Port regression test 156 to Pytests

testsuite/pytests/sli2py_regressions/test_ticket_156.py

@@ -0,0 +1,74 @@
+# -*- coding: utf-8 -*-
+#
+# test_ticket_156.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 numpy as np
+import pytest
+
+
+def test_ticket_156():
+    """
+    Verify that poisson_generator_ps generates identical spike trains for given
+    start and stop times across different simulation resolutions and different targets.
+
+    Protocol:
+    1. poisson_generator_ps projects to two spike_recorders.
+    2. Run for different resolutions, record precise spike times in ms.
+    3. Test all spikes are in (start, stop].
+    4. Test for different results between spike_recorders.
+    5. Test for identical results across resolutions.
+    """
+
+    ps_params = {"origin": 0.0, "start": 1.0, "stop": 2.0, "rate": 12345.0}  # Expect ~ 12.3 spikes
+    resolutions = [0.01, 0.1, 0.2, 0.5, 1.0]
+    simtime = ps_params["stop"] + 2.0
+
+    def single_trial(h):
+        """
+        Returns concatenated spike times recorded by the two spike recorders.
+
+        Asserts that single spike trains fulfill requirements.
+        """
+
+        nest.ResetKernel()
+        nest.resolution = h
+
+        pg = nest.Create("poisson_generator_ps", params=ps_params)
+        srs = nest.Create("spike_recorder", n=2)
+        nest.Connect(pg, srs, syn_spec={"delay": 1.0, "weight": 1.0})
+
+        nest.Simulate(simtime)
+
+        spike_times = srs.get("events", "times")
+
+        # Test that the two recorders recorded different times
+        assert not np.array_equal(*spike_times)
+
+        # Test that all spike times are in (start, stop]
+        all_spike_times = np.concatenate(spike_times)
+        assert all(all_spike_times > ps_params["origin"] + ps_params["start"])
+        assert all(all_spike_times <= ps_params["origin"] + ps_params["stop"])
+
+        return all_spike_times
+
+    # Run trials for each resolution and check all resolutions yield identical spike trains
+    results = [single_trial(h) for h in resolutions]
+    for train in results[1:]:
+        assert np.allclose(train, results[0], atol=1e-15)