You're not using Test::More's tests, even though when you use it, you tell it you will (via tests => 4). I would be inclined to rewrite your tests as follows:

use Test::More tests => 4;
BEGIN {use_ok('Mytest')}

is( Mytest::is_even(0), 1, 'is_even says 0 is even' );
is( Mytest::is_even(1), 0, 'is_even says 1 is not even' );
is( Mytest::is_even(2), 1, 'is_even says 2 is even' );
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s**lil*;  $*=join'',sort split q**;  s;.*;grr; &&s+(.(.)).+$2$1+; $; =
qq-$_-;s,.*,ahc,;$,.=chop for split q,,,reverse;print for($,,$;,$*,$/)
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