Component-based software development regards software construction in terms of conventional engineering disciplines, where the assembly of systems from readily available prefabricated parts is the norm. Because both component-based systems and the stakeholders in component-based development projects differ from traditional software systems, component-based testing also needs to deviate from traditional software testing approaches. Gross first describes the specific challenges related to component-based testing, such as the lack of internal knowledge of a component or the usage of a component in diverse contexts. He argues that only built-in contract testing, a test organization for component-based applications founded on building test artifacts directly into components, can prevent catastrophic failures like the one that caused the now famous Ariane 5 crash in 1996.