Re: [Perlunit-devel] oh dear

[Adam S. <ad...@sp...>]

Piers Cawley (pdc...@bo...) wrote:
> Adam Spiers <ad...@sp...> writes:
> > Adam Spiers (ad...@sp...) wrote:
> >> Think I just found some bad brokenness, although it could be just me
> >> getting hopelessly confused as my brain gets trampled into mush by a
> >> quagmire of exceptions and assertions.  I have a testcase:
> >> 
> >> sub test_this_should_fail {
> >>     my $self = shift;
> >>     $self->assert(sub { $_[0] eq $_[1] or die "$_[0] ne $_[1]" }, 'a', 'b');
> >> }
> >> 
> >> which does not fail.  In fact it behaves identically to
> >> 
> >> sub test_this_should_fail {
> >>     my $self = shift;
> >>     $self->assert(sub { $_[0] eq $_[1] or die "$_[0] ne $_[1]" }, 'a', 'a');
> >> }
> >> 
> >> Can anyone reproduce with latest CVS?
> >
> > Ignore that.  The problem is that the die() from within a
> > Assertion::CodeRef produces an Error::Simple, which gets turned into a
> > Test::Unit::Failure too far up the stack, so if
> > test_this_should_fail() is in AssertTest.pm, it won't work with
> > check_failures().  Argh.  What to do?
> 
> Hmm... I'm thinking.

All I've come up with so far is to change check_failures() to
recognise with Error::Simple and treat it as a Test::Unit::Failure.
But AFAICS T::U::Assertion::CodeRef is the only place which seems to
consider a die() as a Test::Unit::Failure rather than a
Test::Unit::Error, and I don't understand how this inconsistency can
work, since a die from inside a T::U::Assertion::CodeRef will be
indistinguishable from (say) a syntax error inside one.  I only just
figured out the die() -> Error::Simple -> Test::Unit::Error stuff
yesterday, so I may be misunderstanding things, in which case, please
let me know!  If I'm right however, some possible solutions occur to
me:

  - Change T::U::Assertion::CodeRef::do_assertion to rethrow die()
    exceptions as Test::Unit::Failures.  Almost ideal, except for the
    serious flaw that syntax errors in the coderef turn up as
    failures.

  - Change the semantics of T::U::Assertion::CodeRefs so that on
    failure they return($failure_msg) rather than die($failure_msg),
    and on success they return zero (a la shell)?  That would be very
    easy to implement, although confusing in that it's the exact
    opposite of Perl's notions of true/false.

  - Change the semantics of T::U::Assertion::CodeRefs so that on
    failure they throw a Test::Unit::Failure rather than a die().  In
    that case, it would be better to drop the current requirement that
    a coderef has to return true to indicate success, since it would
    no longer be necessary.

The third option is my preference.