diff --git a/uncertainties/test_umath.py b/uncertainties/test_umath.py
index 687c2028..c8555e7c 100644
--- a/uncertainties/test_umath.py
+++ b/uncertainties/test_umath.py
@@ -10,7 +10,6 @@
 from __future__ import absolute_import
 
 # Standard modules
-import sys
 import math
 
 # Local modules:
diff --git a/uncertainties/test_uncertainties.py b/uncertainties/test_uncertainties.py
index f37d0bbe..79c1db90 100644
--- a/uncertainties/test_uncertainties.py
+++ b/uncertainties/test_uncertainties.py
@@ -18,7 +18,6 @@
 from builtins import map
 from builtins import range
 import copy
-import weakref
 import math
 from math import isnan, isinf
 import random