public void WaitAsync_PreCancelled_FailsSynchronously()
{
var semaphore = new BinarySemaphore();
Assert.IsFalse(semaphore.IsLocked);
Assert.AreEqual<int>(0, semaphore.WaitCount);
var token = new CancellationToken(true);
var task0 = semaphore.Wait(token);
// should throw an exception
AssertEx.ThrowsException<AggregateException>(() => { var result = task0.Result; });
Assert.AreEqual<int>(0, semaphore.WaitCount);
Assert.IsTrue(task0.IsCompleted);
Assert.IsTrue(task0.IsFaulted);
}
public void WaitAsync_IsCompleted()
{
Test.Async(async () =>
{
var semaphore = new BinarySemaphore();
Assert.IsFalse(semaphore.IsLocked);
Assert.AreEqual<int>(0, semaphore.WaitCount);
var task0 = semaphore.Wait(none);
var result0 = await task0;
Assert.IsTrue(result0);
Assert.IsTrue(semaphore.IsLocked);
Assert.AreEqual<int>(0, semaphore.WaitCount);
var task1 = semaphore.Wait(none);
await Task.Delay(5); // need brief pause, or waitcount might not be updated
Assert.AreEqual<int>(1, semaphore.WaitCount);
await AssertEx.NeverCompletesAsync(task1);
});
}
public void WaitAsync_Cancel_WithWaiters()
{
Test.Async(async () =>
{
var semaphore = new BinarySemaphore();
Assert.IsFalse(semaphore.IsLocked);
Assert.AreEqual<int>(0, semaphore.WaitCount);
var task0 = semaphore.Wait(none);
var result0 = await task0;
Assert.IsTrue(result0);
var id0 = task0.Id;
Console.WriteLine("task0 id0=" + id0);
var cts1 = new CancellationTokenSource();
var task1 = semaphore.Wait(cts1.Token);
Assert.IsFalse(task1.IsCompleted);
var id1 = task1.Id;
Console.WriteLine("task1 id1=" + id1);
// no token for task2
var task2 = semaphore.Wait(none);
Assert.IsFalse(task2.IsCompleted);
var id2 = task2.Id;
Console.WriteLine("task2 id2=" + id2);
// now have 2 waiting tasks
Assert.AreEqual<int>(2, semaphore.WaitCount);
// cancel the first waiter
cts1.Cancel();
try
{
// for for it to throw
await task1;
}
catch (Exception e)
{
Assert.IsInstanceOfType(e, typeof(OperationCanceledException));
}
// validate cancellation
Assert.IsTrue(task1.IsCanceled);
// validate that lock is still held
Assert.IsTrue(semaphore.IsLocked);
// should now be only 1 waiter
Assert.AreEqual<int>(1, semaphore.WaitCount);
// now release to allow task2 to complete
semaphore.Release();
await task2;
// now validate lock held and no waiters
Assert.IsTrue(task2.IsCompleted);
Assert.IsTrue(semaphore.IsLocked);
Assert.AreEqual<int>(0, semaphore.WaitCount);
// now release lock
semaphore.Release();
Assert.IsFalse(semaphore.IsLocked);
});
}
async Task releasesWaiters()
{
var semaphore = new BinarySemaphore();
Assert.AreEqual<int>(0, semaphore.WaitCount);
var wait0 = await semaphore.Wait(none);
Assert.IsTrue(wait0);
Assert.AreEqual<int>(0, semaphore.WaitCount);
Assert.IsTrue(semaphore.IsLocked);
var task = semaphore.Wait(none);
Assert.IsFalse(task.IsCompleted);
Assert.AreEqual<int>(1, semaphore.WaitCount);
semaphore.Release();
var wait1 = await task;
Assert.IsTrue(wait1);
Assert.IsTrue(semaphore.IsLocked);
Assert.AreEqual<int>(0, semaphore.WaitCount);
}
public void Release_WithoutWaiters_IncrementsCount()
{
var semaphore = new BinarySemaphore();
Assert.IsFalse(semaphore.IsLocked);
var task = semaphore.Wait(none);
Assert.IsTrue(task.Result);
Assert.AreEqual<int>(0, semaphore.WaitCount);
Assert.IsTrue(semaphore.IsLocked);
Assert.IsTrue(task.IsCompleted);
semaphore.Release();
Assert.IsFalse(semaphore.IsLocked);
}
