We propose an algorithm to optically test a fairly complex photonic filter, equipped by thermo-optic actuators. Among the novelties of this approach we can find: (i) the complete independence from spectral measurements, which make the procedure fast and flexible, matching the strict requirements of massive testing, in terms of throughput; and (ii) the cancelation of thermal-cross talk among the building blocks of the photonic circuit, despite the extensive exploitation of thermo-optic actuators.