Test is often seen as a necessary evil; it is a fact of life that ICs have manufacturing defects and those need to be filtered out by testing before the ICs are shipped to the customer. In this paper, we show that techniques and tools used in the testing field can also be (re-)used to create value to (1) designers, (2) manufacturers, and (3) customers alike. First, we show how the test infrastructure can be used to detect, diagnose, and correct design errors in prototype silicon. Secondly, we discuss how test results are used to improve the manufacturing process and hence production yield. Finally, we present test technologies that enable systems of high reliability for safety-critical applications.