A method for testing a batch of material used to obtain layers of fibers includes taking a specimen from the batch of material, exerting a tensile force on the specimen, heating the specimen so as to relax the fibers if the specimen contains stresses, after a predetermined period of time, no longer heating and no longer exerting the tensile force on the specimen, measuring a residual extension of the specimen which corresponds to a variation in length of at least a part of the specimen in the direction of the tensile force, before and after the tensile force, and considering the batch of material not to be compliant if the residual extension exceeds a given threshold.