Bassists are expected to learn bass lines as written or on recording.
They are expected to have a quality instrument (Fender, Lakland, Music Man or comparable) with excellent tone. Excellent tone has as much to do with equipment as it does the technique employed by the instrumentalist.
They are expected to show the ability to play not only in time with the click, but to actually help create the pocket with the drummer.
The bass is must be proficient enough to play octaves notes and tasteful riffs when called for.