Williams ran its 2012 machine in last week's first pre-season test at Jerez after deciding not to use the new car there in order to focus on evaluating the 2013 Pirelli tyres.
But after passing the final nose test as scheduled last Thursday, the new car will be able to hit the track on February 19.
At Jerez last week, Pastor Maldonado said that he was confident about the new machine.
"It's a step," said Maldonado. "We try to look at every single component, everything.
"But all the cars look very similar to last year because the rules are the same.
"It's a small improvement all round the car and we are quite confident that it will be very competitive this year, even better than the previous one."