An exemplary test principle for OPC UA Safety is presented. The OPC UA Safety test is a fully automated verification based on test patterns covering all paths of the OPC UA Safety state machines. Different types of possible correct and incorrect SPDUs, parameters, and interactions with the upper interface of the SafetyProvider / SafetyConsumer are taken into account. These test patterns together with the expected responses/stimulations are stored as an XML document and imported into the test tool software. The test tool executes the complete test patterns while connected to the OPC UA Safety layer under test, compares the nominal with the actual reactions and is recording the results that can be printed out for the test report.
Figure 28 shows the structure of the layer tester for the SafetyProvider and SafetyConsumer.