tests/test-username-newline

forbid username with '\n' at the changelog level

It was already forbidden for ui.username() but no verification were
made for username passed through the commandline.

#!/bin/sh
#

hg init foo
cd foo
touch a


unset HGUSER
echo "[ui]" >> .hg/hgrc
echo "username= foo" >> .hg/hgrc
echo "          bar1" >> .hg/hgrc

hg ci -Am m

rm .hg/hgrc

HGUSER=`(echo foo; echo bar2)` hg ci -Am m

hg ci -Am m -u "`(echo foo; echo bar3)`"

true