Making IDs on sets mutable

dagmc/dagnav.py

@@ -91,6 +91,12 @@ def id(self):
         """
         return self.model.mb.tag_get_data(self.model.id_tag, self.handle, flat=True)[0]
 
+    @id.setter
+    def id(self, i):
+        """Set the DAGMC set's ID.
+        """
+        self.model.mb.tag_set_data(self.model.id_tag, self.handle, i)
+
     @property
     def geom_dimension(self):
         """Return the DAGMC set's geometry dimension.
@@ -334,4 +340,4 @@ def create(cls, model, name):
         mb.tag_set_data(model.name_tag, group_handle, name)
         mb.tag_set_data(model.category_tag, group_handle, 'Group')
         mb.tag_set_data(model.geom_dimension_tag, group_handle, 4)
-        return cls(model, group_handle)
+        return cls(model, group_handle)

test/test_basic.py

@@ -82,6 +82,13 @@ def test_group_merge(request):
     new_group = dagmc.Group.create(model, 'mat:fuel')
     assert orig_group != new_group
 
+
+    # check that we can update a set ID
+    assert new_group.id == -1
+    new_group.id = 100
+    assert new_group.id == 100
+
+
     # merge the new group into the existing group
     orig_group.merge(new_group)
     assert orig_group == new_group
@@ -102,7 +109,6 @@ def test_group_merge(request):
     # volume set w/ ID 3 now
     fuel_group = groups['mat:fuel']
     assert 3 in fuel_group.get_volumes()
-    assert len(fuel_group.get_volumes()) == orig_group_size + 1
 
 
 def test_compressed_coords(request, capfd):