I've had the good fortune not to be in bands where the guitarists have any great interest in bass, although one of the current band's guitarists is able to show me a lick I haven't had problems with playing it (e.g. one time he showed me his simpler version of a line I was screwing up!)
One band I joined the guitarist/songwriter had written all the basslines already, very much in a Bruce Foxton style. My audition was him going through a whole load of them on guitar. I picked them all up I got the gig!