tests/silenttestrunner.py

tests: fix up some import statements caught by Python 3

I'm curious how the import checker manages to be so much more
pedantic in Python 3, but not enough to bother exploring.

Differential Revision: https://phab.mercurial-scm.org/D5240

from __future__ import absolute_import, print_function
import os
import sys
import unittest

def main(modulename):
    '''run the tests found in module, printing nothing when all tests pass'''
    module = sys.modules[modulename]
    suite = unittest.defaultTestLoader.loadTestsFromModule(module)
    results = unittest.TestResult()
    suite.run(results)
    if results.errors or results.failures:
        for tc, exc in results.errors:
            print('ERROR:', tc)
            print()
            sys.stdout.write(exc)
        for tc, exc in results.failures:
            print('FAIL:', tc)
            print()
            sys.stdout.write(exc)
        sys.exit(1)

if os.environ.get('SILENT_BE_NOISY'):
    main = unittest.main