UnitTesting IntelliJ plugins : how to invoke an action ?

Hello,

I'm writing a Vcs plugin (or rather hacking on the hg4idea plugin), and would like to programmatically invoke the "Version Control" > "Update Project" action. How can I do that ?

My TestCase extends from AbstractVcsTestCase, but that does not seem to provide anything to do this.

Thanks for any help,

Willem