A simple way of seeing if one .prove file has different test results from another (used with "prove --state=save")

provediff.pl

#!/usr/bin/env perl                                                                                                                                     

use Modern::Perl;
use App::Prove::State;

my ( $prove1, $prove2 ) = @ARGV;
unless ( -f $prove1 and -f $prove2 ) {
    die "Pass .prove files, please";
}

# XXX Must fix this in App::Prove. We want to be able to read and parse these
# .prove files even if we're in a different directory.
no warnings 'redefine';
local *App::Prove::State::_prune_and_stamp = sub { };
my $first = App::Prove::State->new( { store => $prove1 } )->results;
my %first_tests = map { $_ => $first->test($_) } $first->test_names;

my $second = App::Prove::State->new( { store => $prove2 } )->results;
my %second_tests = map { $_ => $second->test($_) } $second->test_names;

foreach my $test ( sort keys %first_tests ) {
    unless ( exists $second_tests{$test} ) {
        header($prove1, $prove2);
        say "Test '$test' found in '$prove1' but not '$prove2'";
    }
}
foreach my $test ( sort keys %second_tests ) {
    unless ( exists $first_tests{$test} ) {
        header($prove1, $prove2);
        say "Test '$test' found in '$prove2' but not '$prove1'";
        next;
    }

    my $first_result  = $first_tests{$test}->result;
    my $second_result = $second_tests{$test}->result;

    if ( $first_result != $second_result ) {
        header($prove1, $prove2);
        say
          "Test '$test' results are different: $first_result failure(s) versus $second_result failure(s)";
    }
}

sub header {
    my ( $prove1, $prove2 ) = @_;
    state $header_printed = 0;
    return if $header_printed;
    say "provediff results for '$prove1' versus '$prove2'";
    $header_printed = 1;
}