[Checkins] [zopefoundation/zExceptions] 73ef1a: Use `assertIn` to get better errors.

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/zopefoundation/zExceptions
  Commit: 73ef1a01d1575dc7c9bd7c7ace85324721261f06
      https://github.com/zopefoundation/zExceptions/commit/73ef1a01d1575dc7c9bd7c7ace85324721261f06
  Author: Hanno Schlichting <hanno at hannosch.eu>
  Date:   2017-05-15 (Mon, 15 May 2017)

  Changed paths:
    M src/zExceptions/tests/testExceptionFormatter.py

  Log Message:
  -----------
  Use `assertIn` to get better errors.

Don't test `'` quoting in exception messages.