1. Test device ( 2 ) for testing at least one electronic control system ( 1 ), wherein the test device exhibits an addressable physical memory, wherein the test device ( 2 ) is suitable and configured to be connected to the control system ( 1 ), which is to be tested, by means of a data channel; to calculate at least one environment model ( 21 ); and to execute at least one test model ( 22 ), wherein the environment model ( 21 ) can interact by means of the data channel by outputting the environment model data to the control system ( 1 ) and by accepting the control system data from the control system ( 1 ), wherein the test model ( 21 ) can be designed for influencing the environment model ( 22 ), for influencing the calculation of the environment model ( 22 ), and/or for influencing the electronic control system ( 1 ), wherein the environment model ( 21 ) is described, inter alia, by the environment model variables, which are filed at fixed physical addresses in memory locations with the addressable physical memory, wherein the test device ( 2 ) is suitable and configured for modifying the environment model variables, characterized in that the test device ( 2 ) comprises a unit ( 23 ) for allocating, in which the allocation of at least one environment model variable to at least one allocated physical address of the memory is filed so as to be readable.