Britney Spears is "furious" her ex-husband KEVIN FEDERLINE has not been required to undergo a drugs test in their ongoing custody battle, according to reports. Spears lost physical custody of her sons - Sean Preston, two, and Jayden James, one - earlier this month (Oct07), after reportedly ignoring a string of court-imposed demands and skipping mandatory drug tests.. The troubled pop superstar was ordered to submit to random drug tests at an earlier court hearing, after being branded a "habitual, frequent and continuous" user of drugs and alcohol by Los Angeles Superior Court Commissioner Scott Gordon. But Spears, 25, is angered by the apparent preferential treatment the court has shown towards dancer Federline. A close pal tells British newspaper The Sun, "She is furious. She believes the court is more sympathetic towards Kevin."