Complex systems are usually made of heterogeneous components, either hardware or software or both. Component interactions, mostly those
unexpected, are a source of conflict, since one of the main concerns for
system reliability and predictability is precisely this component interaction. This paper reviews a number of approaches, produced over an eight
year period, to component interaction focussing on component interaction
modelling, testing and testing coverage. Other topics such as component
interaction observation and pure monitoring/visualization of component
interactions are outlined.