Checa has been riding the Ducati Panigale R Superbike and giving the Ducati Corse technicians his feedback and information on the bike to aid them in redeveloping and improving the machine.
The Spaniard completed more than 150 laps over three days in perfect conditions and helped the Ducati team a lot with his input.
In a chat with worldsbk.com, Checa, who replaced injured test rider Luca Scassa, said it was emotional to be riding the Panigale again.
"I was pleased to ride the Panigale again and to be fast right away. It was really emotional to work with those people who helped me achieve my past results.
“I hope that my work over these three days has helped the team to further improve the bike, which has really grown a lot recently," said Checa.
“I thank Ducati and the whole development team for having given me the chance to enjoy the excitement of the track once more. I had a lot of fun and who knows; perhaps I'll have another chance to test in the future," he added.
Ducati SBK Project Director, Ernesto Marinelli, said that it was emotional to work with Checa again and added that his input was appreciated.
"It's been emotional and informative working with Carlos once again. There is always something to be learned from a rider with his level of experience and, as is usual with him, feedback has been clear and precise.
“We have carried out an intense testing programme and the fact we've had high temperatures this week has allowed us to work on rear grip and race consistency in extreme conditions such as these. Work that will undoubtedly prove useful in the next races.
"Carlos came here in good shape, to complete more than 150 laps at Mugello with these temperatures is certainly not easy but he's been very consistent throughout," he added.