tests/test-status-inprocess.py

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.

#!/usr/bin/env python
from __future__ import absolute_import, print_function

import sys

from mercurial import (
    commands,
    localrepo,
    ui as uimod,
)

print_ = print


def print(*args, **kwargs):
    """print() wrapper that flushes stdout buffers to avoid py3 buffer issues

    We could also just write directly to sys.stdout.buffer the way the
    ui object will, but this was easier for porting the test.
    """
    print_(*args, **kwargs)
    sys.stdout.flush()


u = uimod.ui.load()

print('% creating repo')
repo = localrepo.instance(u, b'.', create=True)

f = open('test.py', 'w')
try:
    f.write('foo\n')
finally:
    f.close

print('% add and commit')
commands.add(u, repo, b'test.py')
commands.commit(u, repo, message=b'*')
commands.status(u, repo, clean=True)


print('% change')
f = open('test.py', 'w')
try:
    f.write('bar\n')
finally:
    f.close()

# this would return clean instead of changed before the fix
commands.status(u, repo, clean=True, modified=True)