--- a/tests/test_grid.py	Sat Jun 24 14:04:00 2017 -0700
+++ b/tests/test_grid.py	Sat Jun 24 14:48:31 2017 -0700
@@ -49,9 +49,19 @@
     def grid_locations(self, locations):
         """grid locations + test created grid"""
 
+        # create a grid
         grid = LatLonGrid(8, 8)
+
+        # add the items to it
         for geoid, (lat, lon) in locations.items():
             grid.add(geoid, lat, lon)
 
+        # iterate over the grid
+        n_locations = 0
+        for i in range(grid.n[0]):
+            for j in range(grid.n[1]):
+                n_locations += len(grid[(i,j)])
+        assert n_locations == len(locations)
+
 if __name__ == '__main__':
     unittest.main()