public void ForEachIteratesItemsInParallel()
{
var strings = LangTestHelpers.RandomStrings(100, 50);
var results = new ConcurrentQueue <Tuple <int, string> >();
var threadCount = 10;
Parallel.ForEach(
threadCount,
CancellationToken.None,
strings,
it =>
{
Thread.Sleep(10);
results.Enqueue(Tuple.Create(Environment.CurrentManagedThreadId, it));
}
);
Assert.AreEqual(threadCount, results.Select(it => it.Item1).Distinct().Count());
CollectionAssert.AreEquivalent(strings, results.Select(it => it.Item2));
}
public void ForEachObeysCancellationToken()
{
var cancellationTokenSource = new CancellationTokenSource();
System.Threading.Tasks.Task.Run(() =>
{
Thread.Sleep(50);
cancellationTokenSource.Cancel();
});
var itemsConsumed = new ConcurrentQueue <int>();
var itemsFinished = new ConcurrentQueue <int>();
Assert.Throws <OperationCanceledException>(() => Parallel.ForEach(
10,
cancellationTokenSource.Token,
Enumerable.Range(0, 1000).Select(it => { itemsConsumed.Enqueue(it); return(it); }),
it => { Thread.Sleep(5); itemsFinished.Enqueue(it); }
));
CollectionAssert.AreEquivalent(itemsConsumed, itemsFinished);
Assert.GreaterOrEqual(itemsConsumed.Count, 10);
Assert.LessOrEqual(itemsConsumed.Count, 100);
}
public void ForEachTerminatesUponFailure()
{
var threadCount = 12;
int itemsReturned = 0;
try
{
var throwExceptions = new CountdownEvent(threadCount);
var threadsRun = new ConcurrentDictionary <int, int>();
Parallel.ForEach(
threadCount,
CancellationToken.None,
Infinite().Select(it => { itemsReturned = it; return(it); }),
i =>
{
threadsRun.AddOrUpdate(
Thread.CurrentThread.ManagedThreadId,
k => { throwExceptions.Signal(); return(1); },
(k, v) => 1
);
Thread.Sleep(1);
if (throwExceptions.IsSet)
{
throw new InvalidOperationException("test exception");
}
}
);
Assert.Fail("Should have thrown an AggregateException");
}
catch (AggregateException e)
{
Assert.AreEqual(threadCount, e.InnerExceptions.Count);
foreach (var inner in e.InnerExceptions)
{
Assert.IsInstanceOf <InvalidOperationException>(inner);
}
}
}