Test import_od() on empty object.

Author: acolomb

test/test_eds.py

@@ -65,6 +65,8 @@ def test_load_unsupported_format(self):
             canopen.import_od(__file__)
         with self.assertRaisesRegex(ValueError, "''"):
             canopen.import_od('')
+        with self.assertRaisesRegex(ValueError, "''"):
+            canopen.import_od(object())
         with self.assertRaisesRegex(ValueError, "''"):
             filelike_object = io.StringIO()  # no .name attribute
             self.addCleanup(filelike_object.close)