If you do not have access to one of the better alternatives like Test::Inline, you can do the same kind of trick they do in python-land by evaluating the special variables $0 and __FILE__.

### begin_: file metadata
    ### <region-file_info>
    ### main:
    ###   - name: trySelfTestModule
    ###     desc: perl module w/ test script inside
    ### </region-file_info>

### begin_: init perl
    package trySelfTestModule;
    use strict;
    use warnings;
    use vars qw(@ISA @EXPORT 
@EXPORT_OK %EXPORT_TAGS $VERSION);
    use Exporter;
    $VERSION    = 1.00;
    @ISA        = qw(Exporter);
    @EXPORT     = qw(    );

### begin_: test code

    ### test_:  run this test iff this package
        ### is being run directly. We check to
        ### make sure the special variable $0 is
        ### equal to __FILE__ special variable
    if($0 eq __FILE__ ){
        print trySelfTestModule::SayHello();
        };

    if($0 eq __FILE__ ){
        print trySelfTestModule::SayByeBye();
        };
        ###end_test

### begin_: subroutine code

    push @EXPORT_OK, qw(  SayHello  );
    sub SayHello {
        return  "Hello World\n";
    }###end_sub

    push @EXPORT_OK, qw(  SayByeBye  );
    sub SayByeBye {
        return  "ByeBye World\n";
    }###end_sub

### begin_: end perl
    1;
    __END__
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