Re: Show backtrace when tap tests fail

On 2017-09-19 21:37:26 +0100, Dagfinn Ilmari Mannsåker wrote:
> Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com> writes:
>
> > On 09/19/2017 01:31 PM, Andres Freund wrote:
> >> Hi,
> >>
> >> I've had a couple cases where tap tests died, and I couldn't easily see
> >> where / why. For development of a new test I found it useful to show
> >> backtraces in that case - just adding a
> >> use Carp::Always;
> >> at the start of the relevant module did the trick.
> >>
> >> I'm wondering if we shouldn't always do so if the module is
> >> installed. I.e. have PostgresNode or something do something like
>
> I think TestLib would be a better place, since PostgresNode uses TestLib
> and there are some tests that use TestLib but notf PostgresNode.

Fair.

> >> # Include module showing backtraces upon failures. As it's a
> >> non-standard module, don't fail if not installed.
> >> eval { use Carp::Always; }
> >>
> >> Comments?
> >
> > Or maybe Devel::Confess ?
>
> Devel::Confess is more thorough, so +1 on that.

Or just try Devel::Confess first, and if the require fails, go to
Carp::always.

> > In an eval you need a 'require' rather than a 'use', AFAIK.
>
> Yes, because 'use' happens as soon as the statement is parsed at compile
> time, long before the eval { } gets executed. Devel::Confess does its
> setup in the 'import' method (called implicitly by 'use'), so we'd need:
>
> eval { require Devel::Confess; Devel::Confess->import };

My perl's rusty ;)

Greetings,

Andres Freund