Susie Wolff will drive the new Williams FW37 on the first day of testing at the Circuit de Catalunya on Thursday.
The Scot, 32, was named the team's test driver in November after taking part in two practice sessions last year.
Race drivers Valtteri Bottas and Felipe Massa will each get a day and a half in the new car over the following three days of running in Barcelona.
Bottas will drive the car on Friday before Massa takes over on Saturday, and the pair will share the final day.
Wolff will have her position expanded in 2015 to include two runs in Friday practice and two tests.
The move comes after she impressed in an outing in free practice at the German Grand Prix which followed an appearance at Silverstone in July. Her outing at Silverstone ended after less than a lap when her car suffered engine failure.
She hopes one day to become the first woman to race in a grand prix since Lella Lombardi in 1976.
Williams finished third in the constructors' championship in 2014, a year after suffering the worst season in their history, following a major internal restructuring and a switch from Renault to Mercedes engines.