Tests of prototypes and samples from initial production batches are also done in the manufactory. These tests are intended to help development of new products; they are not meant to test all production pieces.
Tests include endurance tests for push-button mechanisms like the chronograph and big date. The date, for instance, is continuously advanced by one century. The setting mechanism is similarly abused with crown rotated thousands of times at a go.
Below: Testing of chronograph pushers
Below: Testing of the setting mechanism
The jumping of the date disc is also recorded by a high-speed camera, to ensure it switches correctly and to help the movement designers fine tune the mechanism.
Another test is an impact test whereby a hammer strikes the watch, sending it flying. This simulates dropping the watch onto the floor.
Yet another test involves placing a watch inside an unlined wood box and then shaking it. Vigorously and continuously.