Toro Rosso officially unveiled its Honda-powered STR13 2018 Formula 1® car with a presentation in the Barcelona paddock ahead of the opening test on Monday morning.
The STR13 made its track debut at a wet Misano circuit last week, with Brendon Hartley at the wheel.
Hartley made a positive start to the official test in Barcelona, setting the eighth fastest time.
"It was a really positive day," said Hartley. "We had no issues at all."
"Obviously we had a lot of test items that we didn't get to complete because of the weather, but I think getting through 93 laps was a great start to the campaign."
"It was really, really positive, all things directed towards Honda. No complaints so far and we had a perfect day in terms of reliability."
Katsuhide Moriyama, Chief Officer for Brand and Communication Operations at Honda, said: “Now we have just eight days to evaluate our work on the track, in order to be ready for the coming season.
"We appreciate the warm support from the fans and hope they enjoy watching us compete in this year’s championship.”