Task

(Given an equal-probability generator of one of the integers 1 to 5
as dice5),   create dice7 that generates a pseudo-random integer from
1 to 7 in equal probability using only dice5 as a source of random
numbers,   and check the distribution for at least one million calls using the function created in   Simple Random Distribution Checker.


Implementation suggestion:
dice7 might call dice5 twice, re-call if four of the 25
combinations are given, otherwise split the other 21 combinations
into 7 groups of three, and return the group index from the rolls.

(Task adapted from an answer here)

def dice5() {
  return entropy.nextInt(5) + 1
}
 
def dice7() {
  var d55 := null
  while ((d55 := 5 * dice5() + dice5() - 6) >= 21) {}
  return d55 %% 7 + 1
}