tests/test-doctest.py

extdiff: allow a preconfigured merge-tool to be invoked

There are three ways to configure an extdiff tool:

    1) cmd.tool = (/path/to/exe optional)
    2) tool = (path/to/exe optional)
    3) tool = sometool someargs

Previously, if no executable is specified in the first two forms, the named tool
must be in $PATH, or the invocation fails.  Since the [merge-tools] section
already has the path to the diff executable, and/or the registry keys to find
the executable on Windows, reuse that configuration for forms 1 and 2 instead of
failing.  We already fallback to [diff-tools] and then [merge-tools] for program
arguments if they aren't specified in the [extdiff] section.

Since this additional lookup only occurs if an executable is not on the $PATH
for the named tool, this is backwards compatible.  For now, we assume the user
knows what he is doing if a path is provided.

This change allows a configuration file like this (assuming beyondcompare3 is
configured in merge-tools), instead of hardcoding system specific a path:

    [extdiff]
    beyondcompare3 =

# this is hack to make sure no escape characters are inserted into the output
import os, sys
if 'TERM' in os.environ:
    del os.environ['TERM']
import doctest

def testmod(name, optionflags=0, testtarget=None):
    __import__(name)
    mod = sys.modules[name]
    if testtarget is not None:
        mod = getattr(mod, testtarget)
    doctest.testmod(mod, optionflags=optionflags)

testmod('mercurial.changelog')
testmod('mercurial.dagparser', optionflags=doctest.NORMALIZE_WHITESPACE)
testmod('mercurial.dispatch')
testmod('mercurial.encoding')
testmod('mercurial.hg')
testmod('mercurial.hgweb.hgwebdir_mod')
testmod('mercurial.match')
testmod('mercurial.minirst')
testmod('mercurial.pathutil')
testmod('mercurial.revset')
testmod('mercurial.store')
testmod('mercurial.subrepo')
testmod('mercurial.templatefilters')
testmod('mercurial.ui')
testmod('mercurial.url')
testmod('mercurial.util')
testmod('mercurial.util', testtarget='platform')
testmod('hgext.convert.cvsps')
testmod('hgext.convert.filemap')
testmod('hgext.convert.subversion')
testmod('hgext.mq')