As part of Microsofts Trustworthy Computing  initiative the company has sought many ways to increase reliability. One approach being extensively investigated and used is Model Based Testing. With a Finite State Machine modeling tool (TMT) successfully deployed and in use by many test groups, a need for more powerful and exible modeling has arisen. Several product groups are exploring the use of the Abstract State Machine Language (AsmL) and its associated test tool (AsmL/T). Results from both approaches have shown an increased ability to nd defects earlier, including in the specification and design stages, as well as achieve higher structural code coverage on the actual systems under test.
Stobie, K. (2005). Model Based Testing in Practice at Microsoft. In Electronic Notes in Theoretical Computer Science (Vol. 111, pp. 5–12). https://doi.org/10.1016/j.entcs.2004.12.004