tests/notcapable

import: add --bypass option

This feature is more a way to test patching without a working directory than
something people asked about. Adding a --rev option to specify the parent patch
revision would make it a little more useful.

What this change introduces is patch.repobackend class which let patches be
applied against repository revisions. The caller must supply a filestore object
to receive patched content, which can be turned into a memctx with
patch.makememctx() helper.

# Disable the $CAP wire protocol capability.

if test -z "$CAP"
then
    echo "CAP environment variable not set."
fi

cat > notcapable-$CAP.py << EOF
from mercurial import extensions, repo
def extsetup():
    extensions.wrapfunction(repo.repository, 'capable', wrapper)
def wrapper(orig, self, name, *args, **kwargs):
    if name in '$CAP'.split(' '):
        return False
    return orig(self, name, *args, **kwargs)
EOF

echo '[extensions]' >> $HGRCPATH
echo "notcapable-$CAP = `pwd`/notcapable-$CAP.py" >> $HGRCPATH