diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
index 79eb8772a74..2e93480b21c 100644
--- a/Lib/test/test_zlib.py
+++ b/Lib/test/test_zlib.py
@@ -1,7 +1,11 @@
 import zlib
 import sys
+import imp
 
-buf = open(sys.argv[0]).read() * 8
+t = imp.find_module('test_zlib')
+file = t[0]
+buf = file.read() * 8
+file.close()
 
 x = zlib.compress(buf)
 y = zlib.decompress(x)