--- a/tests/test-tag
+++ b/tests/test-tag
@@ -73,3 +73,13 @@
 hg branch tag-and-branch-same-name
 hg ci -m"discouraged"
 hg tag tag-and-branch-same-name
+
+echo '% test custom commit messages'
+cat > $HGTMP/editor <<'__EOF__'
+#!/bin/sh
+echo "custom tag message" > "$1"
+echo "second line" >> "$1"
+__EOF__
+chmod +x "$HGTMP"/editor
+HGEDITOR="'$HGTMP'"/editor hg tag custom-tag -e
+hg log -l1 --template "{desc}\n"