Port regression test 156 to Pytests

testsuite/pytests/sli2py_regressions/test_ticket_156.py

@@ -0,0 +1,79 @@
+# -*- 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 check_limits(spks):
+        """Check if all spikes are within the specified limits."""
+        ori = ps_params["origin"]
+        return np.min(spks) > ps_params["start"] + ori and np.max(spks) <= ps_params["stop"] + ori
+
+    def single_trial(h):
+        """Run a single trial with a given resolution."""
+        nest.ResetKernel()
+        nest.SetKernelStatus({"resolution": h})
+
+        pg = nest.Create("poisson_generator_ps", params=ps_params)
+        srs = [nest.Create("spike_recorder") for _ in range(2)]
+
+        for sr in srs:
+            nest.Connect(pg, sr, syn_spec={"delay": 1.0, "weight": 1.0})
+
+        nest.Simulate(simtime)
+        return [nest.GetStatus(sr, "events")[0]["times"] for sr in srs]
+
+    # Run trials for each resolution
+    results = [single_trial(h) for h in resolutions]
+
+    # First test: Check limits
+    assert all(check_limits(np.concatenate(trial)) for trial in results), "Spike times out of bounds"
+
+    # Second test: Different results between targets
+    assert all(not np.array_equal(trial[0], trial[1]) for trial in results), "Spike recorders have identical results"
+
+    # Third test: Equality among runs
+    # Compare spike times across resolutions for each recorder separately
+    for i in range(2):
+        spike_times_across_resolutions = [trial[i] for trial in results]
+        reference_times = spike_times_across_resolutions[0]
+        assert all(
+            np.allclose(reference_times, times, atol=1e-15) for times in spike_times_across_resolutions[1:]
+        ), "Spike times not consistent across resolutions"