Spamassassin false negative for message from text

[Anonymous Monk]

Background:

I'm downloading my twitter feed and saving them into text files and I want to check the likely hood of spam using a perl script with Mail::SpamAssassin. So I followed this post about loading messages from text. All my messages keep getting marked as 'not spam' even when I inject 419 scams.

Question

What am I doing wrong?
Do I have to configure some Spamasssasin files?
Do My messages need to be in a cetain format?
Is there a better alternative for my project?

Details:

code:

 use Mail::SpamAssassin;
 use Mail::Audit;


     open FILE, "<", ~/Messages/twitter_tweet.ema' or die;
     my @lines = <FILE>;

     my $spamtest = Mail::SpamAssassin->new();

     my $mail = $spamtest->parse(\@lines);

     my $status = $spamtest->check($mail);

     print $status->get_report();

    if ($status->is_spam()) {
        print "Totally Spam\n";
     }
     else {
         print "not spam\n";
     }


     $status->finish();
     $mail->finish();
     $spamtest->finish();

errors:

also $status->get_report() prints (no report template found)
I didn't configure spamAssasin I simply started using the perl module
There is a file called ~.spamassassin/user_prefs in my home directory but i didn't touch it