ratio: 0.4679674600393233

lessThan(39, 39) - Expected: false, instead got: true

39 is not less than 39, and in this case the ratio is 1, bigger than the threshold, so it should be double false, aka true.

If any calculation would result in a division by zero, or if either input parameter is Infinity, just return true

There are two kinds of Infinity, positive and negative ones. The negative ones are never tested.