First, start with Test::More, not Test::Simple. Use the convenience functions, like so:

my $authCard = ShopDB::AuthorizeCard->new();
isa_ok( $authCard, 'ShopDB::AuthorizeCard' );
can_ok( $authCard, 'AuthorizeCard' );
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Those convenience methods will save you hassle AND problems like you had. isa_ok() specifically checks definedness for you.