Tex. Transp. Code § 521.2461

The court granting an occupational driver's license under this subchapter may require as a condition of the license that the person submit to periodic testing for alcohol or controlled substances, to be conducted by an entity specified by the court, if the person's license has been suspended, revoked, or canceled under Chapter 524 or 724 or as a result of the person's conviction for an offense relating to the operating of a motor vehicle while intoxicated.