Integration testing, or end-to-end testing, tests how well software components integrate. For large projects there may be several different components that are written by different people or even teams. There is a potential for a breakdown in communcation. For example one component may feed another component by placing a value on a database table.

While unit testing is focused on source code modules, integration testing is concerned about the system as a whole. In this testing data may be fed into the system to watch how it behaves when it reaches your source code and, in turn, how your code affects other components.

It is important to understand the system architecture as whole. Write a formal plan that describes two things: 1) what you plan to test and 2) what you expect the results to be. Document any results that differ from your expected results. They should either be fixed or explained.

Holy Batcars! Don’t miss tomorrow’s blog entry when I will discuss verification testing. Boffo!