First please note that an assumption in your narrative\'s first sentence is incorrect: the commissioning services (including testing) must be contracted directly by the owner, not by the contractor, as it is the owner\'s interests that are being protected. The same company (or individual) may perform the commissioning authority and test engineer roles as long as no design assistance is being provided, and this company/person is not employed by any of the project\'s design and construction companies. Furthermore, it must be written into the commissioning plan that the Commissioning Agent will perform the tasks of a test engineer. Applicable internationally.