The claim that the GNU GPL has never been tested in court, is not true anymore. It has been looked at by various courts in several countries looking at different aspects. This time it was examined whether the GPL breaks antitrust rules in the US. InternetCases reports:

The U.S. Court of Appeals for the Seventh Circuit has issued an opinion in which Judge Easterbrook declares, “[t]he GPL and open-source have nothing to fear from the antitrust laws.” The case is called Wallace v. IBM., No. 06-2454.[…]
Plaintiff Wallace filed an antitrust suit against IBM, Red Hat and Novell, arguing that those companies had conspired to eliminate competition in the operating system market by making Linux available at an “unbeatable” price (free) under the General Public License (“GPL”).[…]
Instead of being a restraint on trade, the court held that the GPL serves to foster creativity, by enabling the free distribution and building of new derivative works.