New Cluster Testing - Best Practice
Not even close to comprehensive, but I'd start with:
1.  Pull the ethernet cable(s) for your public ip interface on your primary/active node.  Confirm the failover.
2.  Pull the SAN fibre cable(s) for your active node. Confirm the failover.
3.  Pull the power cable(s) for you active node.  Confirm the failover.

Those represent the main types of failure that MS Clustering will compensate for in the first place...

I think I'd have my real/prod db detached or offline while I played these games.*