Using basic unit testing techniques we found 25 faults in a core component within a larger component oriented framework after the component had already started to be reused. We found that, even though this particular component had been subject to subsystem and system testing and used for some time, several faults were discovered which seriously would have affected applications using it, especially in terms of reliability. This study clearly indicates the need of a new approach to testing and verification within component-based development and reuse.