tests/test-requires.t

tests: duplicate test for pager for old extension and for in-core pager

When the old pager extension is enabled, I think we should try to be
as BC as reasonable. To help with that, this patch brings back
test-pager.t as of 65a3b4d67a65 (pager: add a test of --pager=no
functionality, 2017-02-06), but under the name test-pager-legacy.t
However, since the behavior has changed in a few cases (notably by no
longer respecting pager.attend), the file is modified to work with the
current version. We will recover some lost BC in coming patches.

Also, to make sure the in-core pager does not depend on the pager
extension being enabled, this patch disables the extension in
test-pager.t. It turns out that pager.attend-$cmd was only supported
when the pager extension was enabled, so the tests are updated to
reflect that. We will need to decide what to do with these.

  $ hg init t
  $ cd t
  $ echo a > a
  $ hg add a
  $ hg commit -m test
  $ rm .hg/requires
  $ hg tip
  abort: index 00changelog.i unknown format 2!
  [255]
  $ echo indoor-pool > .hg/requires
  $ hg tip
  abort: repository requires features unknown to this Mercurial: indoor-pool!
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]
  $ echo outdoor-pool >> .hg/requires
  $ hg tip
  abort: repository requires features unknown to this Mercurial: indoor-pool outdoor-pool!
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]
  $ cd ..

Test checking between features supported locally and ones required in
another repository of push/pull/clone on localhost:

  $ mkdir supported-locally
  $ cd supported-locally

  $ hg init supported
  $ echo a > supported/a
  $ hg -R supported commit -Am '#0 at supported'
  adding a

  $ echo 'featuresetup-test' >> supported/.hg/requires
  $ cat > $TESTTMP/supported-locally/supportlocally.py <<EOF
  > from mercurial import localrepo, extensions
  > def featuresetup(ui, supported):
  >     for name, module in extensions.extensions(ui):
  >         if __name__ == module.__name__:
  >             # support specific feature locally
  >             supported |= set(['featuresetup-test'])
  >             return
  > def uisetup(ui):
  >     localrepo.localrepository.featuresetupfuncs.add(featuresetup)
  > EOF
  $ cat > supported/.hg/hgrc <<EOF
  > [extensions]
  > # enable extension locally
  > supportlocally = $TESTTMP/supported-locally/supportlocally.py
  > EOF
  $ hg -R supported status

  $ hg init push-dst
  $ hg -R supported push push-dst
  pushing to push-dst
  abort: required features are not supported in the destination: featuresetup-test
  [255]

  $ hg init pull-src
  $ hg -R pull-src pull supported
  pulling from supported
  abort: required features are not supported in the destination: featuresetup-test
  [255]

  $ hg clone supported clone-dst
  abort: repository requires features unknown to this Mercurial: featuresetup-test!
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]
  $ hg clone --pull supported clone-dst
  abort: required features are not supported in the destination: featuresetup-test
  [255]

  $ cd ..