Testing in the active sense is the most common way to performverification and validation of systems, but testing in the passivesense has one compelling property: independence. Independencefrom test stimuli and other passive tests opens up for parallel testingand off-line analysis. However, the tests can be difficult to developsince the complete testable state must be expressed using someformalism. We argue that a carefully chosen language togetherwith an interactive work flow, providing immediate feedback, canenable testers to approach passive testing. We have conducted a casestudy in the automotive domain, interviewing experienced testers.The testers have been introduced to, and had hands-on practicewith a tool. The tool is based on Easy Approach to RequirementsSyntax (EARS) and provides an interactive work flow for developingand evaluating test results. The case study shows that i) the testersbelieve passive testing is useful for many of their tests, ii) they seebenefits in parallelism and off-line analysis, iii) the interactive workflow is necessary for writing the testable state expression, but iv)when the testable state becomes too complex, then the proposedlanguage is a limitation. However, the language contributes toconcise tests, resembling executable requirements.

In large-scale embedded system development, requirements are often expressed in natural language. Translating these requirements to executable test cases, while keeping the test cases and requirements aligned, is a challenging task. While such a transformation typically requires extensive domain knowledge, we show that a systematic process in combination with passive testing would facilitate the translation as well as linking the requirements to tests. Passive testing approaches observe the behavior of the system and test their correctness without interfering with the normal behavior. We use a specific approach to passive testing: guarded assertions (G/A). This paper presents a method for transforming system requirements expressed in natural language into G/As. We further present a proof of concept evaluation, performed at Bombardier Transportation Sweden AB, in which we show how the process would be used, together with practical advice of the reasoning behind the translation steps.

The characteristics of systems-of-systems (SoS) present fundamental challenges regarding properties such as safety, security, reliability, and robustness. This is due to the SoS nature where a collection of independent systems cooperate to fulfil certain high-level objectives. Risk analysis is thus an important activity in SoS engineering. This paper presents a risk analysis method which extends the existing STAMP safety analysis method that is based on systems thinking. Our extensions are aimed at coping with other risks than safety, and the usage is tailored to SoS. The method aims at deriving requirements on the constituent systems that will reduce the emergent risks on the SoS as a whole. The method has been applied to a case study of vehicle platooning.

This paper presents the SAGA toolbox. It centers around development of tests, and analysis of test results, on Guarded Assertions (GA) format. Such a test defines when to test, and what to expect in such a state. The SAGA toolbox lets the user describe the test, and at the same time get immediate feedback on the test result based on a trace from the System Under Test (SUT). The feedback is visual using plots of the trace. This enables the test engineer to play around with the data and use an agile development method, since the data is already there. Moreover, the SAGA toolbox also enables the test engineer to change test stimuli plots to study the effect they have on a test. It can later generate computer programs that can feed these test stimuli to the SUT. This enables an interactive feedback loop, where immediate feedback on changes to the test, or to the test stimuli, indicate whether the test is correct and it passed or failed.

While systems of systems (SoS) are starting to reach the market, it is not entirely evident how to analyze safety, and on a high level also security, of such systems. In fact, specific characteristics of SoS, such as independence, changing constitution, evolutionary development, and emergent behavior, provide certain challenges to the safety analysis. In this paper, such challenges are summarized and a systems theoretic safety analysis method, abbreviated as STAMP, is evaluated on an automotive SoS application example. In conclusion, STAMP seems well positioned to serve as a base for a future method for safety and, to a certain degree, security analysis of SoS, although some work remains to be done. The advantages and limitations of the STAMP approach when dealing with SoS are discussed.

An increasing share of the innovations emerging in the vehicular industry are implemented in software. Consequently, vehicular electrical systems are becoming more and more complex with an increasing number of functions, computational nodes and complex sensors, e.g., cameras and radars. The introduction of autonomous functional components, such as advanced driver assistance systems, highlight the foreseeable complexity of different parts of the system interacting with each other and with the human driver. It is of utmost importance that the testing effort can scale with this increasing complexity. In this paper, we review the challenges that we are facing in integration testing of complex embedded vehicular systems. Further, based on these challenges we outline a set of research directions for semi-automated or automated test design and execution in integration testing of vehicular systems. While the discussion is exemplified with our hands-on experience of the automotive industry, much of the concepts can be generalised to a broader setting of complex embedded systems.

Future transportation systems will be a heterogeneous mix of items with varying connectivity and interoperability. A mix of new technologies and legacy systems will co-exist to realize a variety of scenarios involving not only connected cars but also road infrastructures, pedestrians, cyclists, etc. Future transportation systems can be seen as a System of Systems (SoS), where each constituent system - one of the units that compose an SoS - can act as a standalone system, but the cooperation among the constituent systems enables new emerging and promising scenarios. In this paper we investigate how to architect cars so that they can be constituents of future transportation systems. This work is realized in the context of two Swedish projects coordinated by Volvo Cars and involving some universities and research centers in Sweden and many suppliers of the OEM, including Autoliv, Arccore, Combitech, Cybercom, Knowit, Prevas, ÅF-Technology, Semcom, and Qamcom.

Testing is a key activity in industry to verify and validate products before they reach end customers. In hardwarein- the-loop system-level verification of automotive systems, testing is often performed using sequential execution of test scripts, each containing a mix of stimuli and assertions. In this paper, we propose and study an alternative approach for automated system-level testing automotive systems. In our approach, assertion-only test scripts and one (or several) stimulionly script(s), execute concurrently on the test driver. By separating the stimuli from the assertions, with each assertion independently determining when the system under test shall be verified, we seek to achieve three things: 1) tests that better represent real-world handling of the product, 2) reduced test execution time, and 3) increased defect detection. In addition to describing our proposed approach in detail, we provide experimental results from an industrial case study evaluating the approach in an automotive system test environment.

The size and complexity of software in automotive systems have increased steadily over the last decades. Modern vehicles typically contain numerous electrical control units (ECUs), and more and more features require real-time interaction between several dedicated ECUs (e.g., gearbox, brake and engine control units) in order to perform their tasks. Since system safety and reliability must not be adversely affected by this increase in complexity, proper quality assurance is a must. Such quality assurance is often performed by testing the system in different levels of integration throughout the development process. However, the growth of complexity of the system under test aslo affects the testing, making it laborious, difficult and costly. This paper presents a novel method for efficient offline analysis of traces, which has been especially tailored for integration testing of automotive systems. The method exploits the recently defined concept of independent guarded assertion in order to formally describe the events that are relevant for the analysis as well as the expected behavior in those events. The offline analysis is implemented using a standard commercial model checker and has shown good performance in the conducted experiments.

Federated embedded systems (FES) is an approach for systems-of-systems engineering in the domain of cyber-physical systems. It is based on the idea to allow dynamic addition of plug-in software in the embedded system of a product, and through communication between the plug-ins in different products, it becomes possible to build services on the level of a federation of products. In this paper, architectural concerns for FES are elicited, and are used as rationale for a number of decisions in the architecture of products that are enabled for FES, as well as in the application architecture of a federation. A concrete implementation of a FES from the automotive domain is also described, as a validation of the architectural concepts presented.