Romain Grosjean hailed his Haas squad after it was able to fix the brake-by-wire problem which affected his VF-16 on Thursday.
Having enjoyed a relatively smooth start to life in Formula 1 during the first group test at the Circuit de Barcelona-Catalunya, the second session proved to be more problematic for Haas.
Esteban Gutierrez was restricted to only 24 laps across the opening two days of running due to a fuel system issue while Grosjean caused three red flags on Thursday, two due to an issue with the brake-by-wire system.
However, Grosjean was able to rack up 66 laps on Friday, before handing over to Gutierrez, whose additional 25 laps ensured the final day of testing was the most productive for the sport's new team.
"Our final day has been very different from the previous days," said Grosjean.
"It’s was a very positive day for all of us. The guys did an amazing job to understand the problem with the brake-by-wire.
"They got it solved. It was a big relief to be able to drive the car and drive it well.
"There are still a few places where we can improve massively, but we’re working on it. I’m looking forward to getting to the first race now. We can fine tune the car there"