public static void DerivedCancellationTokenSource_Negative()
{
// Test the Dispose path for a class derived from CancellationTokenSource
{
var disposeTracker = new DisposeTracker();
CancellationTokenSource c = new DerivedCTS(disposeTracker);
c.Dispose();
// Dispose() should have prevented the finalizer from running. Give the finalizer a chance to run. If this
// results in Dispose(false) getting called, we'll catch the issue.
GC.Collect();
GC.WaitForPendingFinalizers();
Assert.Throws<ObjectDisposedException>(
() =>
{
// Accessing the Token property should throw an ObjectDisposedException
if (c.Token.CanBeCanceled)
Assert.True(false, string.Format("DerivedCancellationTokenSource: Accessing the Token property should throw an ObjectDisposedException, but it did not."));
else
Assert.True(false, string.Format("DerivedCancellationTokenSource: Accessing the Token property should throw an ObjectDisposedException, but it did not."));
});
}
}
public static void DerivedCancellationTokenSource()
{
// Verify that a derived CTS is functional
{
CancellationTokenSource c = new DerivedCTS(null);
CancellationToken token = c.Token;
var task = Task.Factory.StartNew(() => c.Cancel());
task.Wait();
Assert.True(token.IsCancellationRequested,
"DerivedCancellationTokenSource: The token should have been cancelled.");
}
// Verify that callback list on a derived CTS is functional
{
CancellationTokenSource c = new DerivedCTS(null);
CancellationToken token = c.Token;
int callbackRan = 0;
token.Register(() => Interlocked.Increment(ref callbackRan));
var task = Task.Factory.StartNew(() => c.Cancel());
task.Wait();
SpinWait.SpinUntil(() => callbackRan > 0, 1000);
Assert.True(callbackRan == 1,
"DerivedCancellationTokenSource: Expected the callback to run once. Instead, it ran " + callbackRan + " times.");
}
// Test the Dispose path for a class derived from CancellationTokenSource
{
var disposeTracker = new DisposeTracker();
CancellationTokenSource c = new DerivedCTS(disposeTracker);
Assert.True(c.Token.CanBeCanceled,
"DerivedCancellationTokenSource: The token should be cancellable.");
c.Dispose();
// Dispose() should have prevented the finalizer from running. Give the finalizer a chance to run. If this
// results in Dispose(false) getting called, we'll catch the issue.
GC.Collect();
GC.WaitForPendingFinalizers();
Assert.True(disposeTracker.DisposeTrueCalled,
"DerivedCancellationTokenSource: Dispose(true) should have been called.");
Assert.False(disposeTracker.DisposeFalseCalled,
"DerivedCancellationTokenSource: Dispose(false) should not have been called.");
}
// Test the finalization code path for a class derived from CancellationTokenSource
{
var disposeTracker = new DisposeTracker();
// Since the object is not assigned into a variable, it can be GC'd before the current method terminates.
// (This is only an issue in the Debug build)
new DerivedCTS(disposeTracker);
// Wait until the DerivedCTS object is finalized
SpinWait.SpinUntil(() =>
{
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();
return disposeTracker.DisposeTrueCalled;
}, 500);
Assert.False(disposeTracker.DisposeTrueCalled,
"DerivedCancellationTokenSource: Dispose(true) should not have been called.");
Assert.True(disposeTracker.DisposeFalseCalled,
"DerivedCancellationTokenSource: Dispose(false) should have been called.");
}
// Verify that Dispose(false) is a no-op on the CTS. Dispose(false) should only release any unmanaged resources, and
// CTS does not currently hold any unmanaged resources.
{
var disposeTracker = new DisposeTracker();
DerivedCTS c = new DerivedCTS(disposeTracker);
c.DisposeUnmanaged();
// No exception expected - the CancellationTokenSource should be valid
Assert.True(c.Token.CanBeCanceled,
"DerivedCancellationTokenSource: The token should still be cancellable.");
Assert.False(disposeTracker.DisposeTrueCalled,
"DerivedCancellationTokenSource: Dispose(true) should not have been called.");
Assert.True(disposeTracker.DisposeFalseCalled,
"DerivedCancellationTokenSource: Dispose(false) should have run.");
}
}