Lance Stroll has appeared in Force India colours for the first time – though there has yet to be formal confirmation of his 2019 role.
Stroll has been widely tipped to move to Force India since his father, Lawrence, acquired the squad in the summer.
The young Canadian remained at Williams through 2018 and last week that team announced Robert Kubica as George Russell's 2019 team-mate.
Stroll appeared on track in the VJM11 shortly after 14.00 on the opening day of post-season testing at Yas Marina.
He has been seen wearing the team's full race overalls in the paddock and has since completed an installation lap before returning to the pits
He is set to conclude the day's running for the team, having taken over from Sergio Perez, and will remain in the car on Wednesday.
Once the announcement of Stroll at Force India is complete it will mean all 20 seats for 2019 have been taken, with Alexander Albon confirmed at Toro Rosso on Monday.
Albon is present at Yas Marina with his new team but will not be driving its STR13.
