How to test whether two time ranges overlap?

Question

I need to implement booking functionality and ensure that bookings don't overlap in a Rails app.

The cover? and between? methods aren't quite what I need. I have to ensure uniqueness of a time range when compared to other potential ranges on the same model, and do it efficiently.

I THINK it can be done using overlaps?. The problem is that this returns TRUE for something like this:

(1..5).overlaps?(5..9)
=> true

If I compared a booking that ended right when another started (3:30 - 4:00 versus 4:00 - 4:30), it would say they do overlap, but they technically don't. That would be a problem right?

ValidatesOverlap seems to handle the issue, including edge overlap.

Any suggestions?

Answer 1

def overlap?(x,y)
  (x.first - y.end) * (y.first - x.end) > 0
end

will work. The problem is that Interval uses >=, as you can see in "Test if two date ranges overlap in Ruby or Rails".