MockParameterInfoUIContext context = new MockParameterInfoUIContext<PsiElement>(elt);
parameterInfoHandler.updateUI((DartFunctionDescription)items[0], context);
assertEquals(infoText, parameterInfoHandler.myParametersListPresentableText);
// index check
MockUpdateParameterInfoContext updateContext = new MockUpdateParameterInfoContext(myEditor, myFile);
final PsiElement element = parameterInfoHandler.findElementForUpdatingParameterInfo(updateContext);
assertNotNull(element);
parameterInfoHandler.updateParameterInfo(element, updateContext);
assertEquals(highlightedParameterIndex, updateContext.getCurrentParameter());
}