use Test::More tests => 4;

my @x = 1 .. 5;

is_deeply([p( 3, 'x', @x)], [ @x ]);
is_deeply([p(-3, 'x', @x)], [ @x ]);
is_deeply([p( 7, 'x', @x)], [ @x, 'x', 'x' ]);
is_deeply([p(-7, 'x', @x)], [ 'x', 'x', @x ]);