tests/test-ui-color.py

tests: add a test runner utility that prints nothing when all tests pass

This will be used to run tests through run-tests, which will expect no output
for a unit test that passes successfully.

The motivation for using unit tests instead of the current Python tests is that
they don't require an output file for comparison and that they're easier to write
because of the available tools from unittest (setup, asserts).

import os, sys
from hgext import color
from mercurial import dispatch, ui

# ensure errors aren't buffered
testui = color.colorui()
testui.pushbuffer()
testui.write(('buffered\n'))
testui.warn(('warning\n'))
testui.write_err('error\n')
print repr(testui.popbuffer())

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

ui_ = ui.ui()
ui_.setconfig('ui', 'formatted', 'True')

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

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

runcmd()
print "colored? " + str(issubclass(ui_.__class__, color.colorui))
runcmd()
print "colored? " + str(issubclass(ui_.__class__, color.colorui))