--- a/tests/run-tests.py	Tue Feb 18 19:11:13 2020 +0100
+++ b/tests/run-tests.py	Thu Mar 05 18:10:19 2020 +0100
@@ -1428,7 +1428,7 @@
             )
             hgrc.write(b'[web]\n')
             hgrc.write(b'address = localhost\n')
-            hgrc.write(b'ipv6 = %s\n' % str(self._useipv6).encode('ascii'))
+            hgrc.write(b'ipv6 = %r\n' % self._useipv6)
             hgrc.write(b'server-header = testing stub value\n')
 
             for opt in self._extraconfigopts: