private static List<BucketId> getTestBuckets() {
        List<BucketId> buckets = new ArrayList<>();
        // Get a set of buckets from the same split level
        for (int i = 16; i <= 18; ++ i) {
            for (int j = 0; j < 20; ++ j) {
                buckets.add(new BucketId(i, j));
            }
        }
        // Get a few random buckets at every split level.
        Random randomized = new Random(413);
        long randValue = randomized.nextLong();
        for (int i = minUsedBits; i < 58; ++ i) {
            buckets.add(new BucketId(i, randValue));
        }
        randValue = randomized.nextLong();
        for (int i = minUsedBits; i < 58; ++ i) {
            buckets.add(new BucketId(i, randValue));
        }
        return Collections.unmodifiableList(buckets);
    }
Build a set of buckets to test that should represent the entire bucket space well.
vdslib/src/test/java/com/yahoo/vdslib/distribution/DistributionTestCase.java