tests/test-ui-color.py

tests: stabilize `test-split-legacy-inline-changelog.t` on Windows

The `tar` command is unable to process "C:\path\to\foo.tar" style paths, which
is how `$TESTDIR` is constructed.  It also didn't work with
`$TESTDIR_FORWARD_SLASH`- both failed with:

    tar: Cannot connect to C: resolve failed
    [128]

But `cat` can handle it if the path is quoted, and `tar` can read from stdin.

import os
from mercurial import (
    dispatch,
    ui as uimod,
)
from mercurial.utils import stringutil

# ensure errors aren't buffered
testui = uimod.ui()
testui.pushbuffer()
testui.writenoi18n(b'buffered\n')
testui.warnnoi18n(b'warning\n')
testui.write_err(b'error\n')
print(stringutil.pprint(testui.popbuffer(), bprefix=True).decode('ascii'))

# test dispatch.dispatch with the same ui object
hgrc = open(os.environ["HGRCPATH"], 'wb')
hgrc.write(b'[extensions]\n')
hgrc.write(b'color=\n')
hgrc.close()

ui_ = uimod.ui.load()
ui_.setconfig(b'ui', b'formatted', b'True')

# we're not interested in the output, so write that to devnull
ui_.fout = open(os.devnull, 'wb')


# call some arbitrary command just so we go through
# color's wrapped _runcommand twice.
def runcmd():
    dispatch.dispatch(dispatch.request([b'version', b'-q'], ui_))


runcmd()
print("colored? %s" % (ui_._colormode is not None))
runcmd()
print("colored? %s" % (ui_._colormode is not None))