A couple capi.plot module fixes and an added test.

openmc/capi/plot.py

@@ -1,7 +1,6 @@
 from ctypes import c_int, c_int32, c_double, Structure, POINTER
 
 from . import _dll
-from .core import _DLLGlobal
 from .error import _error_handler
 
 import numpy as np
@@ -31,7 +30,7 @@ class _Position(Structure):
         elif idx == 2:
             return self.z
         else:
-            raise IndexError("{} index is invalid for _Position".format(key))
+            raise IndexError("{} index is invalid for _Position".format(idx))
 
     def __setitem__(self, idx, val):
         if idx == 0:

tests/unit_tests/test_capi.py

@@ -438,3 +438,26 @@ def test_property_map(capi_init):
 
     properties = openmc.capi.plot.property_map(s)
     assert np.allclose(expected_properties, properties, atol=1e-04)
+
+
+def test_position(capi_init):
+
+    pos = openmc.capi.plot._Position(1.0, 1.0, 1.0)
+
+    assert pos[0] == 1.0
+    assert pos[1] == 1.0
+    assert pos[2] == 1.0
+
+    pos[0] = 1.3
+    pos[1] = 1.3
+    pos[2] = 1.3
+
+    assert pos[0] == 1.3
+    assert pos[1] == 1.3
+    assert pos[2] == 1.3
+
+    with pytest.raises(IndexError) as e:
+        pos[3] = 1.3
+
+    with pytest.raises(IndexError) as e:
+        pos[-1] = 1.3