--- a/tests/test-diffdir
+++ b/tests/test-diffdir
@@ -7,6 +7,8 @@ hg ci -m "a" -d "0 0"
 
 echo 123 > b
 hg add b
-hg diff | sed "s/\(\(---\|+++\) [a-zA-Z0-9_/.-]*\).*/\1/"
+hg diff | sed -e "s/\(+++ [a-zA-Z0-9_/.-]*\).*/\1/" \
+              -e "s/\(--- [a-zA-Z0-9_/.-]*\).*/\1/"
 
-hg diff -r tip | sed "s/\(\(---\|+++\) [a-zA-Z0-9_/.-]*\).*/\1/"
+hg diff -r tip | sed -e "s/\(+++ [a-zA-Z0-9_/.-]*\).*/\1/" \
+                     -e "s/\(--- [a-zA-Z0-9_/.-]*\).*/\1/"