internal override IObservable <List <PlaylistItem> > BuildObservable(object param) => Observable.Create <List <PlaylistItem> >(async o =>
 {
     try { o.OnNext(await PlaylistsRepo.GetAllAsync()); }
     catch (Exception e)
     {
         Log.Error(GetType().Name, e.Message);
         o.OnError(e);
     }
     finally { o.OnCompleted(); }
 });
        public async Task Test_GetAllAsync()
        {
            var registryItems = JsonParseHelper.Parse <List <PlaylistItem> >(Resources.json_groups);
            var repoItems     = await Repo.GetAllAsync();

            Assert.That(registryItems.Count == repoItems.Count);
            for (int i = 0; i < registryItems.Count; i++)
            {
                var regItem  = registryItems[i];
                var repoItem = repoItems[i];
                Assert.That(regItem.Id == repoItem.Id);
                Assert.That(regItem.Description == repoItem.Description);
                Assert.That(regItem.Image == repoItem.Image);
                Assert.That(regItem.Name == repoItem.Name);
                Assert.That(regItem.Type == repoItem.Type);
            }
        }