[Checkins] [zopefoundation/Acquisition] 242656: Convert more doctests into unittests.

[GitHub]

  Branch: refs/heads/more-unittests
  Home:   https://github.com/zopefoundation/Acquisition
  Commit: 24265681a79852a717d5ac86157793bcf50dcea0
      https://github.com/zopefoundation/Acquisition/commit/24265681a79852a717d5ac86157793bcf50dcea0
  Author: Hanno Schlichting <hanno at hannosch.eu>
  Date:   2017-09-17 (Sun, 17 Sep 2017)

  Changed paths:
    M src/Acquisition/tests.py

  Log Message:
  -----------
  Convert more doctests into unittests.

Also use `unittest.skipIf/Unless` to skip tests, so the test count
is the same in all test combinations.