In many cases, the documents you signed, but if you are like most of us, you did not read, allow the mechanic to test drive the vehicle. Even if you did not, there is a strong argument that can be made by the shop that the operation of the vehicle was required to repair the vehicle.
That being said, it is recommended that you retain counsel with regards to the citation. You may be able to demonstrate that the vehicle was not to be driven on a roadway. In essence, you would be asking the officer to withdraw the citation. Under your circumstances you describe, this argument may have merit. However, you should consult with an attorney as soon as possible to discuss your case in detail.