my $data = file( shift() )->slurp;

### At dev-time, when this processor is known to be working

my $tst1 = MyApp::Processor->process( $data );
YAML::DumpFile( $file, $data, $test1 );

### Then, sometime later in a test script...

my @files = <test-files/*.yml>;
plan tests => scalar @files;

for my $file ( @tests ) {
    my ( $data, $test1 ) = YAML::LoadFile( $file );
    my $test2 = MyApp::Processor->process( $data );

    eq_or_diff( $test1, $test2, "$file not broken yet!" );
}