The `resources/orientation-event-helpers.js` tests depend on the implementation of the `GenericSensorTest` interface which is defined in [README.md](../generic-sensor/README.md). The Chromium implementation of the `GenericSensorTest` interface is located in [generic_sensor_mocks.js](../resources/chromium/generic_sensor_mocks.js). Other browser vendors should provide their own implementations of the `GenericSensorTest` interface.