testCreateDialog() {
    // Note: this tests simply creating the dialog because that's the only
    // functionality added to this class. Opening or closing effects
    // (editing the actual link) is tested in linkdialog_test.html, but
    // should be moved here if that functionality gets refactored from the
    // dialog to the plugin.
    mockCtrl.$replayAll();

    plugin = new LinkDialogPlugin();
    plugin.registerFieldObject(mockField);

    /** @suppress {visibility} suppression added to enable type checking */
    const dialog = plugin.createDialog(new DomHelper(), mockLink);
    assertTrue(
        'Dialog should be of type goog.ui.editor.LinkDialog',
        dialog instanceof LinkDialog);

    mockCtrl.$verifyAll();
  }
Tests that the plugin's dialog is properly created.
     @suppress {checkTypes} suppression added to enable type checking