use Test::MockRandom 'Some::Other::Package';
use Some::Other::Package 'pin'; # exports pin()

# list of values for rand to use
srand( ( (0) x 4, ( oneish() ) x 4 ); # 0,0,0,0,1,1,1,1

is( pin(), '0000', "rand always zero" );
is( pin(), '9999', "rand always almost one");