Abstract: Circuit testing equipment comprising a computer (110) having stored thereon a boundary scan description language (BSDL) file (111), a netlist (112) and a connections list (113). An adapter (105) connects the computer to a boundary scan bus of a circuit (120) to be tested. The computer is arranged to parse and compile the BSDL file, the netlist and the connections list to generate a data structure which, when combined with a test script (114), permits execution of the test script from the computer through the boundary scan bus. The test script can be IC-specific such that it is valid for a particular IC independent of the circuit in which the IC is located.