diff -r 1bb465fad209 -r 62855e1ce9d8 tests/testlib/pythonpath.sh
--- a/tests/testlib/pythonpath.sh	Wed Apr 08 01:16:57 2020 +0800
+++ b/tests/testlib/pythonpath.sh	Fri May 08 20:36:32 2020 +0800
@@ -3,7 +3,7 @@
 export SRCDIR="`dirname $TESTDIR`"
 if [ -n "$PYTHONPATH" ]; then
     export HGTEST_ORIG_PYTHONPATH=$PYTHONPATH
-    if uname -o | grep -q Msys; then
+    if uname -o 2> /dev/null | grep -q Msys; then
         export PYTHONPATH="$SRCDIR;$PYTHONPATH"
     else
         export PYTHONPATH=$SRCDIR:$PYTHONPATH