IMHO testing is one of those places where you can break some of the "rules" like "don't use stringy eval" or "don't check the boolean status of $@ to see if the eval failed or not". The following works on your example code:

use warnings;
use strict;
use Test::More tests=>12;

ok ! defined eval "use My::Test; 1";
like $@, qr/\bNumber of import parameters is wrong\b/i;
ok ! defined eval "use My::Test qw/foo/; 1";
like $@, qr/\bNumber of import parameters is wrong\b/i;
ok ! defined eval "use My::Test qw/foo bar/; 1";
like $@, qr/\bNumber of import parameters is wrong\b/i;
ok ! defined eval "use My::Test qw/foo bar quz baz/; 1";
like $@, qr/\bNumber of import parameters is wrong\b/i;
ok ! defined eval "use My::Test qw/foo bar quz baz blah/; 1";
like $@, qr/\bNumber of import parameters is wrong\b/i;
ok defined eval "use My::Test qw/foo bar quz/; 1";
ok !$@;
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