tests/remotefilelog-getflogheads.py

tests: use simple mock smtp server instead of deprecated asyncore smtpd

test-patchbomb-tls.t would fail with:
  .../hg/tests/dummysmtpd.py:6: DeprecationWarning: The asyncore module is deprecated and will be removed in Python 3.12. The recommended replacement is asyncio
    import asyncore
  .../hg/tests/dummysmtpd.py:8: DeprecationWarning: The smtpd module is deprecated and unmaintained and will be removed in Python 3.12.  Please see aiosmtpd (https://aiosmtpd.readthedocs.io/) for the recommended replacement.
    import smtpd

The recommended migration path to the standalone asiosmtpd would be overkill.

The tests do not need a full smtp server - we can just use a very simple mock
hack to preserve the existing test coverage.

from mercurial.i18n import _
from mercurial import (
    hg,
    registrar,
)
from mercurial.utils import (
    urlutil,
)

cmdtable = {}
command = registrar.command(cmdtable)


@command(b'getflogheads', [], b'path')
def getflogheads(ui, repo, path):
    """
    Extension printing a remotefilelog's heads

    Used for testing purpose
    """

    dest = urlutil.get_unique_pull_path_obj(b'getflogheads', ui)
    peer = hg.peer(repo, {}, dest)

    try:
        flogheads = peer.x_rfl_getflogheads(path)
    finally:
        peer.close()

    if flogheads:
        for head in flogheads:
            ui.write(head + b'\n')
    else:
        ui.write(_(b'EMPTY\n'))