private T GetOrCreateElement <T>(string id, IProject project, IUnitTestElement parent, ISet <UnitTestElementCategory> categories, Func <UnitTestElementId, T> factory)
where T : Element
{
var elementId = _serviceProvider.CreateId(project, _targetFrameworkId, id);
var element = GetElementById <T>(elementId) ?? factory(elementId);
var invalidChildren = element.Children.Where(x => x.State == UnitTestElementState.Invalid);
_serviceProvider.ElementManager.RemoveElements(invalidChildren.ToSet());
element.Parent = parent;
element.OwnCategories = categories;
_elements[elementId] = element;
return(element);
}
