Williams abandoned a straightline aerodynamic test this week due to bad weather.
The British team's Finnish test driver Valtteri Bottas and the FW33 were ready to roll at the Kemble airfield when the British skies opened, according to Turun Sanomat newspaper.
"With direct tests so limited, we don't want to waste our days in the rain," said Bottas, 21.
"As soon as you put a wheel on the track, you have one test date less. So I didn't drive," he explained. "I went there (to Kemble) and I came back."