[testFile] organize imports

Author: jgrewe

nixio/test/test_file.py

@@ -7,15 +7,15 @@
 # modification, are permitted under the terms of the BSD License. See
 # LICENSE file in the root of the Project.
 import os
-import unittest
+import time
 import h5py
+import unittest
 import numpy as np
-import time
 
 import nixio as nix
-from nixio.exceptions.exceptions import DuplicateName
 import nixio.file as filepy
-from nixio.exceptions import InvalidFile
+from nixio.exceptions import InvalidFile, DuplicateName
+
 from .tmp import TempDir