Hello there! Well, there are a lot of ways you could go about this. I'll list three very easy to implement ones, each with a different approach

One, simply cd into the script directory and run your script from there.

Two, use File::Basename so you can build an absolute path to your test1.txt file using dirname:

#!/usr/bin/env perl
 
use File::Basename;

use strict;
use warnings;

@ARGV = (dirname(__FILE__)."/test1.txt");

while(<>) {
    chomp;
    print "It was $_ that in some stooge like file!\n";
}
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The above code works because your test1.txt file is located in the same directory as your script and therefore, you can use dirname with the __FILE__ variable(or $0) and simply tack on the filename to get a path to your text file.

Three, you could use an absolute path:

#!/usr/bin/env perl

use strict;
use warnings;

@ARGV = ("C:/Scripts/test1.txt");

while (<>) {
    chomp;
    print "It was $_ that I saw in some stooge-like file!\n";
}
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As you can see, there is more than one way to do it. There are still more ways than I have listed, but they should be sufficient :).