tests/test-issue1502.t

run-tests: also follow symlink when update PATH with 'run-tests.py' dir

I'm using 'run-tests.py' from my '$PATH' and use a symlink to get 'run-tests.py'
to in that '$PATH'. There is a handful of test helpers (like f) that needs to be
in the '$PATH' for the test to run, and they are expected to live next to the
'run-tests.py' binary. Using a symlink confuses this logic, so we add to the
'$PATH' both the 'run-tests.py' executable directory, and the actual file
location direction.

http://mercurial.selenic.com/bts/issue1502

Initialize repository

  $ hg init foo
  $ touch foo/a && hg -R foo commit -A -m "added a"
  adding a

  $ hg clone foo foo1
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo "bar" > foo1/a && hg -R foo1 commit -m "edit a in foo1"
  $ echo "hi" > foo/a && hg -R foo commit -m "edited a foo"
  $ hg -R foo1 pull -u
  pulling from $TESTTMP/foo (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  not updating: not a linear update
  (merge or update --check to force update)

  $ hg -R foo1 book branchy
  $ hg -R foo1 book
   * branchy                   1:e3e522925eff

Pull. Bookmark should not jump to new head.

  $ echo "there" >> foo/a && hg -R foo commit -m "edited a again"
  $ hg -R foo1 pull
  pulling from $TESTTMP/foo (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  (run 'hg update' to get a working copy)

  $ hg -R foo1 book
   * branchy                   1:e3e522925eff