Susie Wolff is to have two more Friday practice sessions with Williams this year in, in addition to one of the four in-season test days.
Wolff will again be in action at the British GP, and will also have a chance to drive on Friday at Barcelona.
Last year she drove at Hockenheim – a venue she knew well from the DTM - but with the German GP's future still uncertain, the team has decided to allow her to drive at another track she knows well.
She has already driven the FW37 in one of the winter test days at Barcelona.
Wolff will also drive on one of the test days immediately after the Austrian GP. Teams are obliged to devote two of the four in-season test days to rookies.
"Last season Susie impressed with her performances during FP1 at Silverstone and Hockenheim and we were keen to give her another chance to test in 2015," said deputy team principal Claire Williams.
"She knew the FW36 well and with the FW37 being a gradual evolution, we were keen to utilise this knowledge and get her in the car to help assess and validate the approaches we have taken."
Wolff added: "Our focus this year is to build on the success of 2014 - I've been training hard all winter and I am physically in the best shape I've ever been, so I am ready for the season ahead.
"As official test driver I will have additional time in the FW37 and by correlating this with my work in the simulator, the team can ensure we are getting the best from the car and check how updates are performing.
"All of us drivers on the Williams roster have been working closely together on this and we are ready to give everything we can to the 2015 season."