The verdict in the FIA International Tribunal hearing over the Mercedes and Pirelli tire test will come by Friday, said president Edwin Glasgow during summing up on Thursday.
The four judges heard evidence from the FIA, Mercedes and Pirelli in turn during the seven-hour session at the FIA's headquarters in Paris.
"You will have [the verdict] by tomorrow," said Glasgow. "We will say nothing more than that now."
The FIA opened the hearing by insisting that it did not give permission for the test and that the use of Mercedes' 2013 car made it an automatic breach of the rules.
Mercedes contended that it was effectively only a contractor working for Pirelli and that as the wording of the rules preventing testing with cars that "confirm substantially" to the current rules, Ferrari's use of a 2011 car for tire tests should also be under the microscope.
Pirelli argued that it should be not up before the Tribunal as the FIA does not have any jurisdiction over it.