fix tests that accidentaly got broken (#3543)

Author: GuySten

tests/unit_tests/test_material.py

@@ -738,11 +738,12 @@ def test_material_deplete():
         chain_file=chain,
     )
 
-    for material in depleted_material:
+    for i_step, material in enumerate(depleted_material):
         assert isinstance(material, openmc.Material)
-        assert len(material.get_nuclides()) > len(pristine_material.get_nuclides())
+        if i_step > 0:
+            assert len(material.get_nuclides()) > len(pristine_material.get_nuclides())
 
-    Co58_mat_1_step_0 = depleted_material[0].get_nuclide_atom_densities("Co58")["Co58"]
+    Co58_mat_1_step_0 = depleted_material[0].get_nuclide_atom_densities("Co58").get("Co58", 0.0)
     Co58_mat_1_step_1 = depleted_material[1].get_nuclide_atom_densities("Co58")["Co58"]
     Co58_mat_1_step_2 = depleted_material[2].get_nuclide_atom_densities("Co58")["Co58"]
 

tests/unit_tests/test_materials.py

@@ -38,13 +38,14 @@ def test_materials_deplete():
 
     assert list(depleted_material.keys()) == [pristine_material_1.id, pristine_material_2.id]
     for mat_id, materials in depleted_material.items():
-        for material in materials:
+        for i_step, material in enumerate(materials):
             assert isinstance(material, openmc.Material)
-            assert len(material.get_nuclides()) > 1
+            if i_step > 0:
+                assert len(material.get_nuclides()) > 1
             assert mat_id == material.id
 
     mats = depleted_material[pristine_material_1.id]
-    Co58_mat_1_step_0 = mats[0].get_nuclide_atom_densities("Co58")["Co58"]
+    Co58_mat_1_step_0 = mats[0].get_nuclide_atom_densities("Co58").get("Co58", 0.0)
     Co58_mat_1_step_1 = mats[1].get_nuclide_atom_densities("Co58")["Co58"]
     Co58_mat_1_step_2 = mats[2].get_nuclide_atom_densities("Co58")["Co58"]
 
@@ -53,7 +54,7 @@ def test_materials_deplete():
     # It then decays in the second cooling step (flux = 0)
     assert Co58_mat_1_step_1 > 0.0 and Co58_mat_1_step_1 > Co58_mat_1_step_2
 
-    Ni59_mat_1_step_0 = mats[0].get_nuclide_atom_densities("Ni59")["Ni59"]
+    Ni59_mat_1_step_0 = mats[0].get_nuclide_atom_densities("Ni59").get("Ni59", 0.0)
     Ni59_mat_1_step_1 = mats[1].get_nuclide_atom_densities("Ni59")["Ni59"]
     Ni59_mat_1_step_2 = mats[2].get_nuclide_atom_densities("Ni59")["Ni59"]