How does one test async code using MS Team System Unit Tests

Question

I'm writing some super simple async code. Just saving a file off-thread.

I'd like to test this code using the clever Unit Test framework in Microsoft Visual Studio Team System 2008 .NET XP Extreme Edition blah blah blah...

How?

I'd like to simple block the test method until the method returns. I can imagine some ways to do this, but I'm blown away there aren't any best practices or helper classes around this.

I see a lot for Silverlight, but nothing generic.

Help?