Formula E powertrain manufacturer DS has drafted in Jean-Eric Vergne and Andre Lotterer as development drivers ahead of the 2018/19 season.
DS used Stephane Sarrazin during the two closed group manufacturer tests that took place at the Monteblanco and Calafat circuits in March and April.
The French manufacturer recently began its private testing programme at the Calafat track, with 2017/18 FE points leader Vergne and his Techeetah team-mate Lotterer driving the DS E-TENSE FE 19.
DS currently supplies the Virgin Racing FE squad, but is expected to switch to Techeetah for the start of season five.
"Our Formula E programme is gaining momentum," said Xavier Mestelan Pinon, DS Performance director.
"Even as we continue to battle for this season's remaining race wins and the 2017/2018 titles, development of DS E-TENSE FE 19 is moving forward fast.
"The technical features we decided to incorporate at the design stage of our new Gen2 all-electric car have all been signed off during the first tests.
"We are now starting the development of the different organs.
"For this, we needed experienced and fast drivers, and who better for that than the one who is leading the championship.
"Their feedback is very positive. They confirm we are working in the right direction."
As a customer squad, Techeetah was only able to take part in the official three days of testing allocated to the FE field ahead the current season, with manufacturer squads allowed 15 days of additional private testing.
The Calafat running therefore represents Vergne and Lotterer's first taste of the Gen2 machinery.
"It's been great to experience DS E-TENSE FE 19 and I'm grateful for the opportunity to do so," said Vergne.
"In Formula E, we have very limited time in the car so any opportunity to have some track time is extremely valuable.
"As a customer team, we do not have our own Gen2 car yet, so when the opportunity arose to test the Gen2 car, we simply couldn't say no."
Lotterer added: "[The] DS E-Tense FE 19 is absolutely fantastic to drive, and I can't wait to have some more time in it.
"It has more grip, power, and it will be very interesting to see what the lap time difference will be, as we expect it to drop considerably.
"I'd like to thank DS Performance for the opportunity to drive their Gen2 car."