tests/test-remotefilelog-permissions.t

rust-cpython: prepare for writing tests that require libpython

What I wanted is to disable the "cpython/extension-module<ver>" feature
while building tests executable, but that seems not doable. Instead,
this patch adds new features dedicated for tests.

The make rule is extracted so that we can easily run cargo tests.

Added a minimal test of ref-sharing as an example. More tests will follow.

#require no-windows

  $ . "$TESTDIR/remotefilelog-library.sh"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > EOF
  $ echo x > x
  $ hg commit -qAm x

  $ cd ..

  $ hgcloneshallow ssh://user@dummy/master shallow -q
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)

  $ cd master
  $ echo xx > x
  $ hg commit -qAm x2
  $ cd ..

# Test cache misses with read only permissions on server

  $ chmod -R a-w master/.hg/remotefilelogcache
  $ cd shallow
  $ hg pull -q
  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ cd ..

  $ chmod -R u+w master/.hg/remotefilelogcache

# Test setting up shared cache with the right permissions
# (this is hard to test in a cross platform way, so we just make sure nothing
# crashes)

  $ rm -rf $CACHEDIR
  $ umask 002
  $ mkdir $CACHEDIR
  $ hg -q clone --shallow ssh://user@dummy/master shallow2 --config remotefilelog.cachegroup="`id -g -n`"
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over * (glob)
  $ ls -ld $CACHEDIR/11
  drwxrws* $TESTTMP/hgcache/11 (glob)