System design verification tests - an overview

The test engineering community has a good understanding of physical tests (parametric, environmental, durability, key life tests, etc.) at component level, i.e. what they are and what is the best execution sequence. There are also well defined methods for component characterization and End Of Line (EOL) validation using 1149.1 and 1149.4. The same cannot be stated about system level tests. The quality of the latter typically depends on the test engineer´s experience and the time available for writing the tests. This paper intends to define “system level test” and “functional test” as used in this paper, define the role of functional test in system design verification, state ways in which functional verification/validation can be achieved at different product integration stages, commenting on the commonalities and differences between test requirements at different integration stages, as well as how physical and functional tests should be combined for optimum results (cost, program timing and coverage)