The Swiss team will unveil the Ferrari-powered C34 at 0900 GMT on the same day that Ferrari are also set to reveal their 2015 machine, the SF15-T.
Marcus Ericsson, who joined Sauber from Caterham at the end of last year, will be tasked with driving duties on the opening day of testing at Jerez on February 1.
Fellow new recruit Felipe Nasr - who challenged for the GP2 title last year - will take over for days two and three, before handing back to Ericsson for the fourth and final day.
As it stands, McLaren will be the first team to take the covers off their 2015 car, having set an online launch date of January 29.
Formula1.com will bring you full coverage of every launch, roll-out and unveiling, as well as the latest news from every test as the action ramps up towards the season-opening 2015 Formula 1 Rolex Australian Grand Prix on March 13.