A machine for testing a circuit board of an electrically insulating material includes circuit tracks of an electrically conductive material arranged on one or opposite side surfaces. At least one test surface is provided. The test surface or each of them defines a number of test points electrically insulated relative to one another and arranged in a matrix configuration. For establishing electrically conductive connection between selected test points of the test surface and selected areas, e.g. circuit tracks of the circuit board to be tested, a connector assembly is sandwiched between the one side surface of the circuit board to be tested and the test surface. The connector assembly is a double-sided circuit board having individual connectors arranged on first and second side surfaces of the circuit board and connected through conductors extending through the circuit board in a configuration corresponding to the selected areas of the circuit board to be tested and the selected points of the test surface, respectively.