tests/test-username-newline

use 'x is None' instead of 'x == None'

The built-in None object is a singleton and it is therefore safe to
compare memory addresses with is. It is also faster, how much depends
on the object being compared. For a simple type like str I get:

            | s = "foo" | s = None
  ----------+-----------+----------
  s == None | 0.25 usec | 0.21 usec
  s is None | 0.17 usec | 0.17 usec

#!/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