1. Method for testing the reliability of a testing apparatus which checks a large number of objects of the same type for one feature, generates a feature signal for each object and checks the feature signal for fulfilment of a first condition, a test object being conducted to the testing apparatus after a number of objects and the feature signal of the test object being checked for the fulfilment of a second condition, characterized in that the second condition is that the feature signal of the test object corresponds to a previously entered reference value.