pattern tests
=============

    >>> import re2
    >>> re2.set_fallback_notification(re2.FALLBACK_EXCEPTION)

We should be able to get back what we put in.

    >>> re2.compile("(foo|b[a]r?)").pattern
    '(foo|b[a]r?)'

    >>> re2.set_fallback_notification(re2.FALLBACK_QUIETLY)
