tests/revnamesext.py

tests: remove unnecessary explicit args from `failfilemerge.py`

The `failfilemerge()` function always raises an exception without
looking at its arguments, so let's use `*args` and `**kwargs`.

Differential Revision: https://phab.mercurial-scm.org/D11854

# Dummy extension to define a namespace containing revision names

from __future__ import absolute_import

from mercurial import namespaces


def reposetup(ui, repo):
    names = {b'r%d' % rev: repo[rev].node() for rev in repo}
    namemap = lambda r, name: names.get(name)
    nodemap = lambda r, node: [b'r%d' % repo[node].rev()]

    ns = namespaces.namespace(
        b'revnames',
        templatename=b'revname',
        logname=b'revname',
        listnames=lambda r: names.keys(),
        namemap=namemap,
        nodemap=nodemap,
    )
    repo.names.addnamespace(ns)