RT #47834 After a failed call to ->expect the ->match, and ->after will return undef and ->before will return the content of the accumulator. Earlier they retained the values obtained during the last successful match.
->before will return undef at the first time but later, if we call ->clear_accum, it will start returning the empty string.
CONFIGURE_REQUIRES ExtUtils::MakeMaker 6.70 Some test updates.