 The MP4 @-@ 30 made its début at the first pre @-@ season test at the Circuito de Jerez . The team endured a difficult start , with the RA615H engine suffering from a series of recurring mechanical faults that restricted the team 's running over the four days , and they finished the test having completed the least amount of mileage among those present . The issues that had plagued the car were not resolved in time for the second test at the Circuit de Barcelona @-@ Catalunya , prompting McLaren to replace some parts supplied by Honda with parts that they had developed independently in 2014 . The team finally managed to get some substantial running in during the final test in Barcelona ; after completing just seven laps on the first day , Jenson Button was able to complete over one hundred on the second . However , with two weeks until the opening race , the longest stint of continuous running that the MP4 @-@ 30 had completed was twelve laps of the Barcelona circuit . This distance — 55 @.@ 8 km ( 34 @.@ 7 mi ) — is less than a quarter of a full Grand Prix distance of 307 @.@ 1 km ( 190 @.@ 8 mi ) . 
