discovered mesh loading does not work with obj

test/test_mesh3D.py

+from tempfile import NamedTemporaryFile
 import tfields
 import numpy as np
 import unittest
@@ -22,6 +23,14 @@ class Mesh3D_Check(TensorMaps_Check):
         # that is ok because self._inst could have stale indices etc..
         self.assertTrue(tri.equal(tri_2))
 
+    def test_save_obj(self):
+        out_file = NamedTemporaryFile(suffix='.obj')
+        self._inst.save(out_file.name)
+        _ = out_file.seek(0)  # this is only necessary in the test
+        load_inst = type(self._inst).load(out_file.name)
+        print(self._inst, load_inst)
+        self.demand_equal(load_inst)
+
 
 class Square_Test(Mesh3D_Check, unittest.TestCase):
     def setUp(self):