The case study described in this presentation has taken place at a medical equipment manufacturer. The product developed was a medical x-ray device used during surgery operations. The system generates x-rays (called exposure) and a detector creates images of the patient based on the detected x-ray beams (called image acquisition). The image pipeline is real-time with several images per second, so the surgeon can e.g. see exactly where he is cutting the patient.
The presentation describes the approach that has been taken to develop an automatic testing framework in order to execute reliability test cases and identify reliability issues. To achieve the control of the system under test, the existing hardware interfaces (physical buttons of the different keyboards, handswitches and footswitches) were used to inject the system with actions (with the use of LabVIEW). This has been done to minimize the so-called probe effect.
The expected results of the test cases have been automatically retrieved from the log files generated by the system. This way the test framework could react on system failures immediately, without wasting valuable test time on scarce test systems. The log files were used to extract information about the performed actions and failures in order to measure the MTBF (Mean Time Between Failures) of different critical system functions (like start-up of the system, and image acquisition). The Crow-AMSAA model for reliability measurements has been chosen to report reliability metrics to the organization. A Return-On-Investment calculation has been performed to get buy-in from senior management who provided additional funding to further develop the testing framework, and to apply the same ideas to different products and projects.
The presentation explains the points which were crucial for the success of this approach to automated reliability testing and briefly explains future plans and extensions (e.g. operational profiles).