public async Task UpdateAsyncUsesIdentityComparerGivenAtConstruction()
{
IEnumerable <IntWrapper> originalItems = new IntWrapper[] { 1, 2, 3 };
IEnumerable <ItemChange <IntWrapper> > changes = new ItemChange <IntWrapper>[]
{
new ItemChange <IntWrapper>(ChangeType.Updated, 2)
};
var loader = new AsyncLoader <IntWrapper>(
Seq.ListBased,
loadDataAsync: _ => Task.FromResult(originalItems),
fetchUpdatesAsync: (_, __) => Task.FromResult(changes),
identityComparer: new IntWrapperComparer(),
eventContext: new RunInlineSynchronizationContext());
await loader.LoadAsync(); // load original items
loader.CollectionChanged += (s, e) =>
{
// Verify that the resulting change was exactly the incoming change
e.Should().Equal(changes);
};
await loader.UpdateAsync(); // --- Perform ---
// Verify that no changes to the int values in the collection were made
loader.Should().Equal(new IntWrapper[] { 1, 2, 3 }, (x, y) => x.Value == y.Value);
}
public async Task UpdateAsyncDoesNotAddOrRemoveItemsForUpdateItemChange()
{
IEnumerable <int> originalItems = new int[] { 1 };
IEnumerable <ItemChange <int> > changes = new ItemChange <int>[] { new ItemChange <int>(ChangeType.Updated, 1) };
var loader = new AsyncLoader <int>(
Seq.ListBased,
loadDataAsync: tok => Task.FromResult(originalItems),
fetchUpdatesAsync: (items, tok) => Task.FromResult(changes));
await loader.LoadAsync();
loader.Should().Equal(new[] { 1 }); // sanity check
await loader.UpdateAsync(); // --- Perform ---
loader.Should().Equal(new[] { 1 });
}
public async Task UpdateAsyncCanRemoveSingleItemFromLoader()
{
IEnumerable <int> originalItems = new int[] { 1 };
IEnumerable <ItemChange <int> > changes = new ItemChange <int>[] { new ItemChange <int>(ChangeType.Removed, 1) };
var loader = new AsyncLoader <int>(
Seq.ListBased,
loadDataAsync: tok => Task.FromResult(originalItems),
fetchUpdatesAsync: (items, tok) => Task.FromResult(changes));
await loader.LoadAsync();
loader.Should().NotBeEmpty(); // sanity check
await loader.UpdateAsync(); // --- Perform ---
loader.Should().BeEmpty();
}
public void LoadAsyncClearsPreviousContents()
{
IEnumerable <int> originalItems = new[] { 1, 2, 3 };
IEnumerable <int> loadedItems = new[] { 4, 5, 6 };
var loadFunc = Substitute.For <Func <CancellationToken, Task <IEnumerable <int> > > >();
loadFunc.Invoke(Arg.Any <CancellationToken>()).Returns(Task.FromResult(originalItems), Task.FromResult(loadedItems));
var loader = new AsyncLoader <int>(seqFactory: Seq.ListBased, loadDataAsync: loadFunc);
loader.LoadAsync(); // initial load
loader.Should().BeEquivalentTo(originalItems); // sanity check
loader.LoadAsync(); // --- Perform ---
loader.Should().BeEquivalentTo(loadedItems);
}
public async Task CanUpdateEmptyLoaderWithEmptyChanges()
{
var loader = new AsyncLoader <int>(
seqFactory: Seq.ListBased,
fetchUpdatesAsync: (_, __) => Task.FromResult(Enumerable.Empty <ItemChange <int> >()));
await loader.UpdateAsync(); // --- Perform ---
loader.Should().BeEmpty();
}
public async Task LoadAsyncPreservesItemsAddedDuringLoad()
{
IEnumerable <int> itemsToLoad = new[] { 2, 3, 4 };
var loadTask = new TaskCompletionSource <IEnumerable <int> >();
var loader = new AsyncLoader <int>(seqFactory: Seq.ListBased, loadDataAsync: tok => loadTask.Task);
// --- Perform ---
var loadComplete = loader.LoadAsync(); // Will get stuck, waiting for loadTask to complete
loader.Conj(1);
loader.Should().BeEquivalentTo(new[] { 1 }); // sanity check
loadTask.SetResult(itemsToLoad); // complete loading
await loadComplete; // wait for LoadAsync to finish
loader.Should().BeEquivalentTo(new[] { 1, 2, 3, 4 });
}
public async Task UpdateAsyncRetainsOrder()
{
IEnumerable <int> originalItems = new int[] { 1, 2, 3 };
IEnumerable <ItemChange <int> > changes = new ItemChange <int>[]
{
new ItemChange <int>(ChangeType.Updated, 2),
new ItemChange <int>(ChangeType.Added, 4)
};
var loader = new AsyncLoader <int>(
Seq.ListBased,
loadDataAsync: tok => Task.FromResult(originalItems),
fetchUpdatesAsync: (items, tok) => Task.FromResult(changes));
await loader.LoadAsync(); // load original items
await loader.UpdateAsync(); // --- Perform ---
loader.Should().Equal(new[] { 1, 2, 3, 4 });
}