If you want to play it safe and check that a package contained in test_v1.pm isn't loaded by a use package; statement somewhere else, insert the following code at the top of the test_vN.pm files. This won't protect you against loading more than one test_vN.pm file, but if that does happen, and you have warnings enabled (which you always should, of course), you should see some "Subroutine redefined" warnings (Update: I hope that test_v1.pm and test_v2.pm defining at least a few of the same subs is a safe assumption).

use Module::Runtime qw/module_notional_filename/;
BEGIN {
    for my $package (qw/ Foo Foo::Bar /) {
        my $fn = module_notional_filename($package);
        die "$package already loaded from $INC{$fn}"
            if exists $INC{$fn};
        $INC{$fn} = __FILE__;
    }
}
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