Testing is an important validation activity particularly for real-time systems. We are interested to testing duration systems which are an extension of real-time systems, we consider that the specification of duration systems is described by a Duration graphs. Duration graphs are an extension of timed graphs and are suitable for modeling the accumulated times spent by computations in the duration systems.

In this paper, we present a testing method for duration systems. First, we use the approximation method extending the specification model to another called approximate model containing the digitization computations. Second, we demonstrate that it is possible to generate tests from the approximate model and we prove that all errors detected with the approximate model exist in the implementation. Then, we present a method for testing duration systems by using the approximate model