HWA's Stoffel Vandoorne says his recent test for the Mercedes ABB FIA Formula E squad is "very important" for his future.
The HWA operation will be taken over by Mercedes at the end of the 2018/19 season as the manufacturer prepares for its FE debut in season six.
Vandoorne's move to FE with HWA began with a call from Mercedes boss Toto Wolff and the ex-McLaren Formula 1 driver - alongside Venturi's Edoardo Mortara - drove the season six Mercedes car for the first time at Varano.
Mercedes completed 527km of running during its three-day test at the end of March which used two of the 15 allocated days of testing that each manufacturer has ahead of the 2019/20 season.
When asked how important the test was for Vandoorne's long-term future in FE, he told Autosport: "Of course, it's very important and very valuable for us because we've come into this year planning for the long term.
"We've had a lot of running to do and gone through a lot of learning curves. But everything we learn carries over to next year."
He added: "It's always exciting to take a new car to the track. Something that's been built from zero. For me to be the first driver to take it out on track was a nice touch to it as well.
"The goal of that test was mainly to do mileage, and that's something we successfully achieved.
"We managed a lot of laps, which was impressive for the first rollout of something that came from nothing, started from zero.
"It's a long road ahead. There's still a lot of work to do, but it was a positive start. And now the real development [of the season six car] will start from here."
Vandoorne's first season in FE has been impacted by reliability issues that HWA has encountered in its debut season.
A run of driveshaft problems required an update from HWA ahead of the Rome E-Prix and Vandoorne took his first podium finish moments before a suspected driveshaft failure occurred.
Asked about conclusions that could be drawn from the Belgian's test with Mercedes, Vandoorne said: "I'm obviously one of their drivers now, with HWA. Gary [Paffett] and Edo as well. We'll see whatever brings next year.
"It would be nice to be part of that team obviously. A manufacturer coming in is something important, we've seen the power they have when they come into a series like this. They can push the team a big step forward.
"From my side, I'm trying to do the best job I can. Trying to guide them in the best direction.
"We've had a steep learning curve at the start of this year, we know that there's still a lot more to come, a lot more issues to solve."
Vandoorne added that he was not aware of when Mercedes was likely to make a call on its 2019/20 driver line-up, although Autosport has been told that a decision would not be taken before the summer.