Japan's Sato, who has raced for Jordan, Honda and Super Aguri in F1, set the fastest times of the three at Spain's Circuit de Catalunya.

BBC: Buemi poised for Toro Rosso seat

However, he has not competed since this year's Spanish Grand Prix in April, when Honda-backed Super Aguri went out of business.

BBC: Sato to test for Toro Rosso again

The support from Magma Group, led by former Ford and Maserati executive Martin Leach, ends fears that the Honda-powered Super Aguri would be unable to take part in the Australian Grand Prix at Melbourne on Sunday.

CNN: Magma Group come to aid of Super Aguri