A federal judge has granted certification of a class of consumers in antitrust litigation asserting that Apple Inc. conspired with publishers to fix the price of electronic books.

The ruling on Friday came ahead of a damages trial set for this summer against Apple over the alleged conspiracy aimed at devouring Amazon.com’s hold on a $9.99 price point for e-books. In a related order on Friday, U.S. District Judge Denise Cote in the Southern District of New York also struck the opinions of one of Apple’s damages experts and most of those of a second expert.