Testing method for a micro electro-mechanical system, comprising the steps of: i) feeding said system to be tested on a first tray; ii) collecting said system from said first tray; and iii) verifying correct operation of said system collected from said first tray; iv) acquiring at least one parameter associated with: - the presence or otherwise of said system on said first tray; and/or - the fact that said system matches or otherwise a correct identification code; and/or - correct or incorrect orientation and/or position of said system on said first tray; said step iv) being performed prior to said step ii); characterised in that said step iv) comprises the step v) of optically scanning said system; said step v) comprising the step vi) of using at least one camera which acquires an image of said system on said first tray and step vii) of lighting said system on said first tray; step iv) comprising the steps of: viii) identifying on the basis of said parameter whether said system must be discarded or tested; ix) leaving said system on said first tray if it has to be discarded; said step ii) being performed if said system has to be tested; said step iv) comprising step x) of acquiring said parameter in a first direction parallel to a direction of forward movement of said first tray; said step iv) comprising step xi) of maintaining an acquisition device at a fixed distance from said tray measured in a second direction, which is transverse to the first direction; said method further comprising the steps of: xii) moving a collecting device and said acquisition device integrally relative to each other in said first direction; and xiii) moving said collecting device with respect to said acquisition device in said second direction and in a third direction transverse to said first and second direction (Y, Z). i) feeding said system to be tested on a first tray; ii) collecting said system from said first tray; and iii) verifying correct operation of said system collected from said first tray; iv) acquiring at least one parameter associated with: - the presence or otherwise of said system on said first tray; and/or - the fact that said system matches or otherwise a correct identification code; and/or - correct or incorrect orientation and/or position of said system on said first tray; - the presence or otherwise of said system on said first tray; and/or - the fact that said system matches or otherwise a correct identification code; and/or - correct or incorrect orientation and/or position of said system on said first tray; characterised in that said step iv) comprises the step v) of optically scanning said system; said step v) comprising the step vi) of using at least one camera which acquires an image of said system on said first tray and step vii) of lighting said system on said first tray; viii) identifying on the basis of said parameter whether said system must be discarded or tested; ix) leaving said system on said first tray if it has to be discarded; xii) moving a collecting device and said acquisition device integrally relative to each other in said first direction; and xiii) moving said collecting device with respect to said acquisition device in said second direction and in a third direction transverse to said first and second direction (Y, Z).