A test controller controlled by a design entity sends at least one closed type command of a closed loop architecture test flow to an arbiter of a vendor test platform controlled by a vendor entity, wherein the test controller controls nondeterministic testing on a protected integrated circuit (IC) integrated into an electronic assembly, as performed by test equipment hardware within the vendor test platform, without the design entity disclosing an underlying design of the protected IC to the vendor entity. In response to the test controller receiving at least one response of the at least one closed type command, from the arbiter interface passing the at least one closed type command directly through the test equipment hardware to the protected IC, determining, by the test controller, based on the at least one response, a next at least one closed type command of the closed loop architecture test flow to send to the arbiter.