public void TestCancellation()
{
var sut = new ExplicitCancellation();
var cts = new CancellationTokenSource();
var cancellationToken = cts.Token;
var numbers = new int[] { 1, 2, 3, 4 };
var source = sut.Generate(cancellationToken, numbers);
var sequence1 = sut.Squre(source, cancellationToken);
var sequence2 = sut.Squre(source, cancellationToken);
var merged = sut.FanIn(cancellationToken, sequence1, sequence2);
// pass a CancellationToken to the enumerator.
var sequence = merged.GetConsumingEnumerable(cancellationToken);
// consumes first one.
var value = sequence.FirstOrDefault();
Assert.True(value > 0);
// Cancellation is not a synchronized operation.
cts.Cancel();
// An OperationCancelledException will be thrown when get next item from the collection.
Assert.Throws <OperationCanceledException>(() => sequence.FirstOrDefault());
}
public void TestCancellation_during_enumerating()
{
var sut = new ExplicitCancellation();
var cts = new CancellationTokenSource();
var cancellationToken = cts.Token;
var numbers = new int[] { 1, 2, 3, 4 };
var source = sut.Generate(cancellationToken, numbers);
var sequence1 = sut.Squre(source, cancellationToken);
var sequence2 = sut.Squre(source, cancellationToken);
var merged = sut.FanIn(cancellationToken, sequence1, sequence2);
var sequence = merged.GetConsumingEnumerable(cancellationToken);
Assert.Throws <OperationCanceledException>(() =>
{
foreach (var n in sequence)
{
// cancel at the first iteration.
cts.Cancel();
// It will be thrown at the next iteration.
}
});
}