diff --git a/tests/tests.py b/tests/tests.py
index 4b408d5..61533d0 100644
--- a/tests/tests.py
+++ b/tests/tests.py
@@ -675,7 +675,7 @@ def test_save_as_mofile(self):
             os.close(fd)
             po = polib.pofile(reffile, autodetect_encoding=False, encoding=encoding)
             po.save_as_mofile(tmpfile1)
-            subprocess.call([msgfmt, '--no-hash', '--endianness=%s' % sys.byteorder, '-o', tmpfile2, reffile])
+            subprocess.call([msgfmt, '--no-hash', '--endianness=%s' % sys.byteorder, '--no-convert', '-o', tmpfile2, reffile])
             try:
                 f = open(tmpfile1, 'rb')
                 s1 = f.read()