A computer-implemented method for testing control devices, comprising the steps of: • Providing and operating at least two control devices, wherein each control device comprises multiple functions, including at least one function dependent on at least one condition and at least one invariant function; • Providing and operating a test routine which tests the respective operated control devices with regard to their function; • Dividing the functions to be tested into at least two groups within the respective control devices, wherein a first group comprises functions which by user definition are classified as safety-relevant functions and wherein all further groups comprise the remaining functions; • Testing each of the functions of the at least two groups; • Determining to what extent a tested function per control device has a connection to at least one tested function from at least one other group in the same control device; • Combining tested functions of the first group with respectively connected and tested functions from all other groups within the respective control device by forming cross products between the respective functions; • Creating respective first intermediate results of each of the combinations; • Determining, by forming cross products between the respective functions, the extent to which a tested function of the first group from a first control device has a connection to at least one tested function from a second control device; • Creating respective second intermediate results of respective combinations between the at least two control devices; • Consolidating the first intermediate results and second intermediate results into a combined test result; • Providing the combined result. • Providing and operating at least two control devices, wherein each control device comprises multiple functions, including at least one function dependent on at least one condition and at least one invariant function; • Providing and operating a test routine which tests the respective operated control devices with regard to their function; • Dividing the functions to be tested into at least two groups within the respective control devices, wherein a first group comprises functions which by user definition are classified as safety-relevant functions and wherein all further groups comprise the remaining functions; • Testing each of the functions of the at least two groups; • Determining to what extent a tested function per control device has a connection to at least one tested function from at least one other group in the same control device; • Combining tested functions of the first group with respectively connected and tested functions from all other groups within the respective control device by forming cross products between the respective functions; • Creating respective first intermediate results of each of the combinations; • Determining, by forming cross products between the respective functions, the extent to which a tested function of the first group from a first control device has a connection to at least one tested function from a second control device; • Creating respective second intermediate results of respective combinations between the at least two control devices; • Consolidating the first intermediate results and second intermediate results into a combined test result; • Providing the combined result.