tests/test-check-jshint.t

copies-rust: make the comparison aware of the revision being current merged

This make no significant performance change in practice (all ±2%) in practice,
but it will help us to distinct between some semantically different cases later
on.

Differential Revision: https://phab.mercurial-scm.org/D9498

#require test-repo jshint hg10

  $ . "$TESTDIR/helpers-testrepo.sh"

run jshint on all tracked files ending in .js except vendored dependencies

  $ cd "`dirname "$TESTDIR"`"

  $ testrepohg locate 'set:**.js' \
  > 2>/dev/null \
  > | xargs jshint