As testing often consumes over 40% of the typical project development effort, there is great need for optimizing the testing effort. In addition, as the cost of fixing defects is dramatically lower when fixing those close to where they were introduced, finding defects in the early life-cycle phases is critical. TTCN-3 (Testing and Test Control Notation), developed at ETSI and standardized by the ITU-T, enables testers to specify test cases for the various types of testing, and supports reuse of test artifacts. We have used TTCN-3 as a complete test solution in the development of network element software. This paper presents the benefits we have observed during system development and provides a comparison with other testing practices deployed in our organization.