tests/test-dispatch.py

reachableroots: return NULL if we're throwing an exception

Based on my reading of [0] and surrounding sections, if we want an
exception to be properly raised when something goes wrong in the C
code, we need to make sure we return NULL here. Do so.

https://docs.python.org/2/extending/extending.html#back-to-the-example

import os
from mercurial import dispatch

def testdispatch(cmd):
    """Simple wrapper around dispatch.dispatch()

    Prints command and result value, but does not handle quoting.
    """
    print "running: %s" % (cmd,)
    req = dispatch.request(cmd.split())
    result = dispatch.dispatch(req)
    print "result: %r" % (result,)


testdispatch("init test1")
os.chdir('test1')

# create file 'foo', add and commit
f = open('foo', 'wb')
f.write('foo\n')
f.close()
testdispatch("add foo")
testdispatch("commit -m commit1 -d 2000-01-01 foo")

# append to file 'foo' and commit
f = open('foo', 'ab')
f.write('bar\n')
f.close()
testdispatch("commit -m commit2 -d 2000-01-02 foo")

# check 88803a69b24 (fancyopts modified command table)
testdispatch("log -r 0")
testdispatch("log -r tip")