tests/heredoctest.py

tests: restore 'python' and '$TESTDIR/' for dummyssh invocation

This is a backout of 46727fea7a00, and a partial backout of c3ecbf694904.

Windows won't execute 'dummyssh' directly, presumably because CreateProcess()
doesn't know how to execute a bash script:

   $ hg clone -e "dummyssh" ssh://user@dummy/cloned sshclone
   remote: 'dummyssh' is not recognized as an internal or external command,
   remote: operable program or batch file.
   abort: no suitable response from remote hg!
   [255]

With the restoration of python as the executable, $TESTDIR needs to be restored
for these invocations, because python won't search $PATH for 'dummyssh':

   $ hg clone -e "python dummyssh" ssh://user@dummy/cloned sshclone
   remote: python: can't open file 'dummyssh': [Errno 2] No such file or directory
   abort: no suitable response from remote hg!
   [255]

import sys

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:
            exec(c, globalvars)
        except Exception as inst:
            print(repr(inst))