Thanks for the ideas!

I slept on the problem and on second, closer look in the documentation https://metacpan.org/pod/Test::Script#script_runs

interpreter_options -- Array reference of Perl options to be passed to
+ the interpreter. Things like -w or -x can be passed this way. This m
+ay be either a single string or an array reference.
[download]

So I just extended the script run line

    script_runs [ @{$scriptNargs} ], { exit => 0, interpreter_options 
+=> '-d' }, $test_run_name;
[download]

tldr; Thanks for the ideas, fortunately the author already has covered this use case.