tests/test-username-newline.t

status: add a flag to terse the output (issue4119)

This adds an experimental flag -t/--terse which will terse the output. The terse flag
will respect other flags which filters the output. The flag takes a string
whose value can be a subsequence of "marduic" (the order does not matter here.)

Ignored files are not considered while tersing unless -i flag is passed or 'i'
is there is the terse flag value.

The flag is experimental for testing as there may be cases which will produce
strange results with the flag. We can set the terse on by default by simply
passing 'u' to the cmdutil.tersestatus().

This patch also adds a test file with tests covering the new feature.

  $ hg init
  $ touch a

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

  $ hg ci -Am m
  adding a
  abort: username 'foo\nbar1' contains a newline
  
  [255]
  $ rm .hg/hgrc

  $ HGUSER=`(echo foo; echo bar2)` hg ci -Am m
  abort: username 'foo\nbar2' contains a newline
  
  [255]
  $ hg ci -Am m -u "`(echo foo; echo bar3)`"
  transaction abort!
  rollback completed
  abort: username 'foo\nbar3' contains a newline!
  [255]