Harden event nuclide check. Make testing more explicit

Author: pshriwise

include/openmc/nuclide.h

@@ -84,6 +84,9 @@ class Nuclide {
   double collapse_rate(int MT, double temperature, span<const double> energy,
     span<const double> flux) const;
 
+  //! Return the ZAID identifier for this nuclide.
+  int zaid() const { return 10000 * Z_ + 10 * A_ + metastable_; }
+
   //============================================================================
   // Data members
   std::string name_; //!< Name of nuclide, e.g. "U235"

src/collision_track.cpp

@@ -202,11 +202,10 @@ void collision_track_record(Particle& particle)
   int cell_id = model::cells[cell_index]->id_;
   std::string nuclide {};
   int nuclide_id {-1};
-  if (particle.type() != ParticleType::electron() && particle.type() != ParticleType::positron())
-  {
+  if (particle.event_nuclide() != NUCLIDE_NONE) {
     const auto* nuclide_ptr = data::nuclides[particle.event_nuclide()].get();
     nuclide = nuclide_ptr->name_;
-    nuclide_id = 10000 * nuclide_ptr->Z_ + 10 * nuclide_ptr->A_ + nuclide_ptr->metastable_;
+    nuclide_id = nuclide_ptr->zaid();
   }
   int universe_id = model::universes[particle.lowest_coord().universe()]->id_;
   double delta_E = particle.E_last() - particle.E();

tests/unit_tests/test_collision_track.py

@@ -145,7 +145,11 @@ def test_photon_particles(run_in_tmpdir, model):
 
         assert len(source) < 200
 
-        allowed_particles = set(openmc.ParticleType(p) for p in ['photon', 'electron'])
+        allowed_particles = (openmc.ParticleType.PHOTON, openmc.ParticleType.ELECTRON)
 
         for point in source:
-            assert openmc.ParticleType(point['particle']) in allowed_particles
+            particle_type = openmc.ParticleType(point['particle'])
+            assert particle_type in allowed_particles
+
+            if particle_type == openmc.ParticleType.ELECTRON:
+                assert point['nuclide_id'] == -1