Follow-Through (Forbes.com) Forbes.com - In the year since our cover story on former Israeli commando Amnon Landan and Mercury Interactive, the Sunnyvale, Calif. software company has taken hostile fire on multiple fronts. Mercury sells testing tools that catch glitches in software programs and make Web and business programs run smoothly. It is grappling with new competition from open source vendors like JUnit and OpenSTA, which offer testing software for free. It's also facing pricing pressure from larger competitor IBM. Mercury stock has tumbled 20 since July.