Testing, testing.

Conceivable test strategy:

First, perform a fuzz test(/unit test? Something computationally intensive and time consuming) while performing a code review.

Next, check all direct inputs.
-Do one greater than max allowed,
-the max allowed, and
-one less than the max allowed,
-also flip of those for 'less than'/'min' -- this is all similar to
-Also conceivably maxint and minint equivalence partitioning
-input incorrect types
-null input, and
-maximum-length input.
-anything else suggested by the code review

Third, pairwise testing on all inputs.

Fourth, data comparisons