SQL Server cluster failover
Failover clustering works to provide constant service in the event of a failure (defining a failure as an "abnormal termination of the previously active application, server, system, or network" - http://en.wikipedia.org/wiki/Failover).  Manual manipulation (start, restart, pause, and stop) upon the service being clustered (SQL Server, File Services, etc.) does not qualify as an abnormal termination of the service.

If I recall, at least in Windows Server 2008, you can simulate a failover test case in the Failover Management Console under Administration Tools.  Check this out for a list of testing methods: http://blogs.technet.com/b/vipulshah/archive/2009/06/17/failover-cluster-testing-methods.aspx