fix access time test

Author: d-w-moore

irods/test/data_obj_test.py

@@ -3308,17 +3308,18 @@ def test_access_time__issue_700(self):
         data_path= iRODSPath(self.coll.path,
             unique_name(my_function_name(), datetime.now())
             )
+
+        time.sleep(2)
+
         with self.sess.data_objects.open(data_path,"w") as f:
             f.write(b'_')
+
+        # At this point, the access_time should be earlier than the modify_time; next we will
+        # test that a read() will the update the access timestamp to be equal or greater.
         with self.sess.data_objects.open(data_path,"r") as f:
             f.read()
-
         data = self.sess.data_objects.get(data_path)
-
-        # The difference between the two timestamps should be positive but less than a second.
-        time_difference = data.access_time - data.modify_time
-        self.assertGreaterEqual(time_difference, timedelta(seconds=0))
-        self.assertLessEqual(time_difference, timedelta(seconds=1))
+        self.assertGreaterEqual(data.access_time, data.modify_time)
 
 if __name__ == "__main__":
     # let the tests find the parent irods lib