Sauber's February statement said de Silvestro will undertake "on track testing, simulator training, as well as mental and physical preparation", with the goal being "to gain her super license and prepare for a race seat in formula one for 2015".
The Swiss newspaper Blick said de Silvestro, from Thun in Switzerland, is set to make her F1 test debut at the end of April.
She said this week: "Formula one has always been my dream."
Asked how realistic that dream is, she answered: "If I do everything right, there is a good chance I will get there at some point."
However, given the current nature of midfield F1, de Silvestro must be considered third in line at Sauber, behind the well-sponsored reserve driver Giedo van der Garde and the 'Russian rescue deal'-linked Sergey Sirotkin.
Veteran Blick correspondent Roger Benoit said: "The chance that de Silvestro will ever race for Sauber in formula one is about one per cent."