public async Task Operation_Cancelled_Before_Dispatch_Does_Not_Execute()
{
var cts = new CancellationTokenSource();
var loader = new SimpleDataLoader <IEnumerable <User> >((ct) => Users.GetAllUsersAsync(ct));
var task = loader.LoadAsync();
cts.Cancel();
loader.Dispatch(cts.Token);
bool wasCancelled;
try
{
var users = await task;
wasCancelled = false;
}
catch (TaskCanceledException)
{
wasCancelled = true;
}
wasCancelled.ShouldBe(true);
Users.GetAllUsersCalledCount.ShouldBe(0, "Fetch delegate should not be called");
}
public async Task Result_Is_Cached()
{
var loader = new SimpleDataLoader <IEnumerable <User> >((ct) => Users.GetAllUsersAsync(ct, 20));
var task = loader.LoadAsync();
loader.Dispatch();
var result1 = await task;
result1.ShouldNotBeNull();
result1.Count().ShouldBe(2);
// Load again. Result should be cached
var task2 = loader.LoadAsync();
task2.Status.ShouldBe(TaskStatus.RanToCompletion);
var result2 = await task2;
// Results should be the same instance
result2.ShouldBeSameAs(result1);
Users.GetAllUsersCalledCount.ShouldBe(1);
}
public async Task Operation_Can_Be_Cancelled()
{
var cts = new CancellationTokenSource();
var loader = new SimpleDataLoader <IEnumerable <User> >((ct) => Users.GetAllUsersAsync(ct, 20));
var task = loader.LoadAsync();
cts.CancelAfter(5);
loader.Dispatch(cts.Token);
bool wasCancelled;
try
{
var users = await task;
wasCancelled = false;
}
catch (TaskCanceledException)
{
wasCancelled = true;
}
wasCancelled.ShouldBe(true);
Users.GetAllUsersCalledCount.ShouldBe(1);
}
public async Task Immediate_Exception_Is_Bubbled_Properly()
{
var loader = new SimpleDataLoader <IEnumerable <User> >(Users.ThrowExceptionImmediatelyAsync);
var task = loader.LoadAsync();
loader.Dispatch();
try
{
await task;
}
catch (Exception ex) when(ex.Message == "Immediate")
{
// This is what should happen
}
}
