How do you open a zip file using watir-webdriver?

My test suite has a cucumber front end with a ruby backend, running the latest version of watir-webdriver and its dependencies atop the latest version of OSX. My cucumber environment is setup to execute in Firefox.

The export feature of our app creates a zip file but to test the import feature, I need the contents of the zip file.

My actual test needs to unpack that zip file and select the individual files in it for use in testing the import feature of our web application.

Can anyone point me to a reference that can help me figure out how to write that?