tests/helpers-testrepo.sh

revset: filter first/last members by __and__ operation

This replaces 'if y in subset' with '& subset'. first(null) and last(wdir())
are fixed thanks to fullreposet.__and__.

This also revealed that first() and last() don't follow the order of the
input set. 'ls & subset' is valid only if the ordering requirement is 'define'
or 'any'.

No performance regression observed:

  revset #0: limit(0:9999, 100, 9000)
  0) 0.001164
  1) 0.001135
  revset #2: 9000 & limit(0:9999, 100, 9000)
  0) 0.001224
  1) 0.001181
  revset #3: last(0:9999, 100)
  0) 0.000237
  1) 0.000199

# The test-repo is a live hg repository which may have evolution
# markers created, e.g. when a ~/.hgrc enabled evolution.
#
# Tests are run using a custom HGRCPATH, which do not
# enable evolution markers by default.
#
# If test-repo includes evolution markers, and we do not
# enable evolution markers, hg will occasionally complain
# when it notices them, which disrupts tests resulting in
# sporadic failures.
#
# Since we aren't performing any write operations on the
# test-repo, there's no harm in telling hg that we support
# evolution markers, which is what the following lines
# for the hgrc file do:
cat >> $HGRCPATH << EOF
[experimental]
evolution=createmarkers
EOF