The ACLU and East Baton Rouge teachers’ union are suing the parish school board over a teacher drug-testing policy they argue is unconstitutional.The lawsuit asks a judge to halt further testing until the case is resolved.At issue is a policy the plaintiffs say subjects any teacher injured on the job to a drug test. They believe that testing without suspicion of drug use amounts to an unconstitutional search.It is not immediately clear from the filing when the policy took effect, and a school board spokesman could not immediately be reached Tuesday. Schools are on holiday break.