OPA matcher for sap.ui.commons.MessageBox

Hi all,

I am coding UI test with opa5. How can I catch a messageBox?

I tried the following code. But, it doesn't work

iShouldSeeConfirmPopup: function(sTitle) {
  return this.waitFor({
       controlType: "sap.ui.commons.MessageBox",
       matchers: function(oControl) {
            return oControl.getTitle() === sTitle;
       },
       success: function(oControls) {
            ok(true, "I see a confirm popup");
       },
       errorMessage: "Did not find confirmation popup"
  });
}

Maybe, sap.ui.commons.MessageBox doesn't support getTitle().

Please teach me how to solve this problem. Thanks