Component testing is generally used for testing a software component, normally by a not big team of programmers.
A component commonly comprises a set of smaller units that together form an object. For traditional software there isn’t accurate differentiation between units and components. The only difference is that components are larger and each of them normally comprises some units. Therefore, component testing is nearly equal to unit testing.
Black-box testing approach is more in line with such objects as components. Black-box testing techniques or usage-based testing techniques can be used. Additionally, some recent work has been focused on adapting traditional testing techniques to work for object-oriented systems, which attempts to adapt use cases and design template suggestions in software testing as well as in product development.
The growing use of software development ground on commercial-off-the shelf components and component based software development has also changed human’s appreciation of component testing. Thus, components are much more significant. This increases the need to assure and show the individual components quality.
Independent testing and certification of software components is a key factor to the possible chooses, use, and adoption of certain software components.
Consequently, independent verification and validation by third-party participants are usually conducted in such cases.
If we are talking about the testing techniques used the situation is equal to system testing, where black-box and usage-based techniques prevail, but at a smaller scale.