Ahead of the 'official' pre-season test, three teams have yet to confirm their full line-ups.

With less than 24 hours before the cars take to the track, only Red Bull, AlphaTauri, Aston Martin and Williams have confirmed their plans for the entire test, while Mercedes and Haas have only confirmed their driver line-ups for the opening days.

While the 'unofficial' - in that they didn't pay for it - test at Barcelona was all about reliability and mileage, this week's test will see the teams raise the ante as they look at outright pace and the updates required for the opening races.

Ferrari (439) completed the most laps in Spain, ahead of Mercedes (393), McLaren (364) and Red Bull (358), while Alfa Romeo completed just 176 and Haas a meagre 160.

Sainz (236) was the driver with the most laps to his tally, ahead of Ricciardo (211), Russell (209), Albon (207) and Verstappen (206), while poor Valtteri Bottas managed just 55 in his Alfa Romeo.

However, while the focus will be on pace, some teams will still need to work on reliability, and, of course, there's that little matter of porpoising. McLaren appear to be on top of the phenomenon, and Ferrari claims it is also getting there, but what of Mercedes and the others?

With the first of the upgrades appearing the cars will no doubt look a little different also, while we should also get further insight into how well the rules overhaul is working in terms of dirty air and overtaking, not to mention slipstreaming, which Charles Leclerc fears could be an issue this year.

"The main objective of the test this week is to build on the learning from the track session in Barcelona and to start to increase the performance of the car," admits Williams Head of Vehicle Performance, Dave Robson. "We got a useful preview in Barcelona and although the cars were only back in Grove for a few days before being transported to Bahrain, we were able to do quite a lot of work on them, which should help us to exploit the best performance this week.

"Conditions in Bahrain will be more demanding than they were in Spain, with the hotter track temperatures affecting the tyre performance and the stronger wind gusts challenging the aero characteristics much harder.

"This will be an excellent opportunity to test the car in a different environment and to use the data we gather to predict how the car will perform throughout the season ahead.

As in Spain, the each day's running will be split into two sessions, the morning running getting underway at 07:00 (GMT) and ending at 11:00 for lunch. Testing resumes at 12:00 before concluding at 16:00.

With the season opener taking place just one week later, the next few days should give greater insight into the pecking order, certainly in the first stage of the season before the 'circus' heads back to Europe.

Team	Thu 10	Fri 11	Sat 12
Mercedes	Hamilton/Russell	TBC	TBC
Red Bull	Perez	Verstappen	Perez/Verstappen
Ferrari	Leclerc/Sainz	TBC	TBC
McLaren	Ricciardo/Norris	Ricciardo	Norris
Alpine	Ocon/Alonso	TBC	TBC
AlphaTauri	Gasly	Tsunoda	Gasly/Tsunoda
Aston Martin	Vettel/Stroll	Vettel/Stroll	Stroll/Vettel
Williams	Albon	Latifi	Latifi/Albon
Alfa Romeo	Zhou/Bottas	Bottas/Zhou	Zhou/Bottas
Haas	Fittipaldi	Schu/Magnussen	Magnussen/Schu