Magnussen and new team-mate Nico Hulkenberg completed a busy programme for the American-registered operation with more than 2200 kilometres between them.
“As always you come into this winter test with a plan, and then we expect to be having to change the plan because of issues and things like that,” Magnussen explained.
“We didn't really have to. We got through it all.”
The 30-year-old logged 514 kilometres of running on Saturday alone – the most of any driver in a single session across the three days.
Hulkenberg added 416km to that tally on the same day in a strong conclusion to pre-season running.
Encouragingly for the Magnussen, the VF-23 looks to have built on the foundations laid a year ago when the team made significant strides forwards after two difficult seasons rooted to the back of the field.
Magnussen sees positives in new Haas
“It's different. The car's different, there's different rules. There's traits that feel different,” he began.
“But it's just good to know, we put a soft tyre on then did a bit of a qualifying simulation and they actually felt good and I think the lap time we did look like still in the midfield somewhere.
“So that's a good starting point. It's going to be exciting to see how we actually go in qualifying next Saturday.”
Haas boss Guenther Steiner has suggested the midfield pack is so condensed that there is no longer a midfield, just a gaggle of teams behind the leader three.
It's a view shared by Magnussen who singled out Aston Martin as a team that caught his eye.
“It's the usual suspects at the front and then maybe Aston Martin looked really impressive these three days,” he said.
“I think they may have taken a big step but after that there's this big group of teams that it's very difficult to see where you are.”
The 2023 Formula 1 season kicks off with the Bahrain Grand Prix this weekend, Free Practice 1 getting underway at 14:30 local time (22:30 AEDT) on Friday.