Testing device for an active optical sensor

A testing device for an active optical sensor, comprising:

• an imaging optical system that includes at least a first optical element and a second optical element, the first optical element and the second optical element each having a beam-forming effect;
• wherein the imaging optical system is configured to be situated with respect to a surroundings interface of an active optical sensor to be tested, in such a way that light beams emitted by the active optical sensor into the surroundings of the active optical sensor and portions of the emitted light beams reflected or scattered from the surroundings to the active optical sensor in each case pass through the imaging optical system, and the first optical element and the second optical element being configured to guide incoming light beams over an optical path of the testing device in such a way that the light beams are imaged over a distance that is shorter than a predefined measuring distance, which an inherent measuring distance of an active optical sensor to be tested.