diff --git a/tests/test_filter_distribcell/test_filter_distribcell.py b/tests/test_filter_distribcell/test_filter_distribcell.py
index 40f8dd69b5..e604d94daf 100644
--- a/tests/test_filter_distribcell/test_filter_distribcell.py
+++ b/tests/test_filter_distribcell/test_filter_distribcell.py
@@ -93,7 +93,7 @@ class DistribcellTestHarness(TestHarness):
 
             if i == 2:
                 sha512 = hashlib.sha512()
-                sha512.update(outstr)
+                sha512.update(outstr.encode('utf-8'))
                 outstr = sha512.hexdigest()
 
             # Write results to a file.