Mocking FacesContext

I am trying to add some unit tests to a JSF application. This application didnt rely heavily on any best practices, so many service methods use the FacesContext to pull data from managed session beans like so:

(this is inside a util class)

  public static Object getPageBean(String beanReference) {
      FacesContext fc = FacesContext.getCurrentInstance();
      VariableResolver vr = fc.getApplication().getVariableResolver();
      return vr.resolveVariable(fc, beanReference);
  }

What would be the best way to mock this? I am using groovy so i have a few more options for creating classes that i cant normally create.

in my case i was able to mock it in pure groovy. i provide a map of MockBeans that it can return:

private FacesContext getMockFacesContext(def map){
        def fc = [
          "getApplication": {
            return ["getVariableResolver": {
              return ["resolveVariable": { FacesContext fc, String name ->
                return map[name]
              }] as VariableResolver
            }] as Application
          },
          "addMessage": {String key, FacesMessage val ->
            println "added key: [${key}] value: [${val.getDetail()}] to JsfContext messages"
          },
          "getMessages": {return null}
        ] as FacesContext;
        return fc;
      }