--- a/.hgignore	Tue Nov 14 23:15:18 2017 +0100
+++ b/.hgignore	Mon Dec 11 09:33:04 2017 +0100
@@ -6,7 +6,7 @@
 \.swp$
 \.orig$
 \.rej$
-\.err$
+^tests/.*\.err$
 ^tests/easy_run.sh$
 ^build/
 ^dist/