Merge branch 'fix-crash-on-occupancy-int64'

* accept diffpy.structure.Atom occupancy of np.int64 type

Resolve #18.

Author: pavoljuhas

src/diffpy/srreal/structureconverters.py

@@ -142,7 +142,7 @@ def _fetchDiffPyStructureData(adpt, stru):
     aa = AdapterAtom()
     for a0 in stru:
         aa.atomtype = a0.element
-        aa.occupancy = a0.occupancy
+        aa.occupancy = float(a0.occupancy)
         aa.anisotropy = a0.anisotropy
         # copy fractional coordinates
         aa.xyz_cartn = a0.xyz

src/diffpy/srreal/tests/teststructureadapter.py

@@ -60,6 +60,16 @@ def test_createStructureAdapterTypes(self):
         self.assertTrue(type(adpt3) is DiffPyStructureAtomicAdapter)
         return
 
+    def test_createStructureAdapter_int64_occupancy(self):
+        """Check Structure conversion when occupany is of numpy.int64 type.
+        """
+        self.nickel[0].occupancy = numpy.int64(0)
+        self.nickel[1].occupancy = numpy.int64(1)
+        adpt = createStructureAdapter(self.nickel)
+        self.assertEqual(0.0, adpt.siteOccupancy(0))
+        self.assertEqual(1.0, adpt.siteOccupancy(1))
+        return
+
     def test_pickling(self):
         '''check pickling of StructureAdapter instances.
         '''