Abstract: A real-world vehicle includes multiple data sources that generate sensor data that is spatially-mapped to a real-world region; a data fusion system is configured to fuse or integrate (i) the spatially-mapped sensor data with (ii) virtual data, that has been generated outside of the vehicle or generated independently of the operation of the vehicle, and is spatially-mapped to a virtual world. This enables a fusion of the real and virtual worlds which enables a self-driving car to interact not only with the physical world but also to virtual objects introduced into the path of the car (e.g. by a test or development engineer) to test how well the car and its autonomous driving systems cope with the virtual object.