Renault seems pleased with the results.
Robert Kubica drove the second test in a modified 2012 Renault F1 car, at the Paul Ricard track on Wedensday. This was done to further test his readiness to return to the F1 racing level.
The first test in Valencia was positive and Robert was happy to do the test and also happy to learn he can actually come back. Before the test he was not so sure, but after driving the car and managing some very good lap times, his confidence grew. He said he's ~90% certain he can come back and be competitive.
After that, Kubica reportedly did some tests in the simulator and he was as fast as Nico Hulkenberg, which says a lot.
Kubica said for L'Equipe: "It is necessary to go step by step. I have come a long way. Don't forget that. My doubts about my capacities have disappeared with these two days of tests. I am no longer afraid of not being at the level but there remains a way to go."
However, it's a fact that Robert did not drive the 2017 car with a race setup, which would let him experience the 100% stress that drivers feel with new wider tyres and the engine at 100% power.
"He has so far only driven an old car, with a detuned engine, with demonstration tyres. He has not been submitted to the stresses of a race nor run with other cars" - Renault managing director Cyril Abiteboul.