diff --git a/tests/test_merge.py b/tests/test_merge.py
index 06ee559..9d7b1af 100644
--- a/tests/test_merge.py
+++ b/tests/test_merge.py
@@ -1,3 +1,4 @@
+import io
 import os
 import sys
 import unittest
@@ -21,8 +22,7 @@ def file_names_from(file_paths):
 
 class TestMerge(unittest.TestCase):
     def setUp(self):
-        if not hasattr(sys.stdout, "getvalue"):
-            self.fail("need to run in buffered mode")
+        sys.stdout = io.StringIO()
 
     def _validate_merged_three(self, merged):
         self.assertEqual(len(merged.cells), 6)