tests/heredoctest.py

run-tests: always define a custom-bin directory

We are always generating `python` / `python3` executable and we will soon often
generate a `hg` executable. So let's always make it a thing. This will help us
to make sure we have the appropriate binary available to all script. On both
linux and Windows.

Differential Revision: https://phab.mercurial-scm.org/D11044

from __future__ import absolute_import, print_function

import sys


def flush():
    sys.stdout.flush()
    sys.stderr.flush()


globalvars = {}
lines = sys.stdin.readlines()
while lines:
    l = lines.pop(0)
    if l.startswith('SALT'):
        print(l[:-1])
    elif l.startswith('>>> '):
        snippet = l[4:]
        while lines and lines[0].startswith('... '):
            l = lines.pop(0)
            snippet += l[4:]
        c = compile(snippet, '<heredoc>', 'single')
        try:
            flush()
            exec(c, globalvars)
            flush()
        except Exception as inst:
            flush()
            print(repr(inst))