public void NotCollectedIfSubscriberIsNotTheCallbackTarget()
{
WeakReference wr = null;
new Action(() =>
{
var subscriber = new TestSubcriber();
wr = new WeakReference(subscriber);
// This creates a closure, so the callback target is not 'subscriber', but an instancce of a compiler generated class
// So MC has to keep a strong reference to it, and 'subscriber' won't be collectable
MessagingCenter.Subscribe <TestPublisher>(subscriber, "test", p => subscriber.SetSuccess());
})();
GC.Collect();
GC.WaitForPendingFinalizers();
Assert.IsTrue(wr.IsAlive); // The closure in Subscribe should be keeping the subscriber alive
Assert.IsNotNull(wr.Target as TestSubcriber);
Assert.IsFalse(((TestSubcriber)wr.Target).Successful);
var pub = new TestPublisher();
pub.Test();
Assert.IsTrue(((TestSubcriber)wr.Target).Successful); // Since it's still alive, the subscriber should still have received the message and updated the property
}
public void SubscriberShouldBeCollected()
{
new Action(() =>
{
var subscriber = new TestSubcriber();
MessagingCenter.Subscribe <TestPublisher>(subscriber, "test", p => Assert.Fail());
})();
GC.Collect();
GC.WaitForPendingFinalizers();
var pub = new TestPublisher();
pub.Test(); // Assert.Fail() shouldn't be called, because the TestSubcriber object should have ben GCed
}
public void StaticCallback()
{
int i = 4;
_subscriber = new TestSubcriber(); // Using a class member so it doesn't get optimized away in Release build
MessagingCenter.Subscribe <TestPublisher>(_subscriber, "test", p => MessagingCenterTestsCallbackSource.Increment(ref i));
GC.Collect();
GC.WaitForPendingFinalizers();
var pub = new TestPublisher();
pub.Test();
Assert.IsTrue(i == 5, "The static method should have incremented 'i'");
}
public void StaticCallback()
{
int i = 4;
var subscriber = new TestSubcriber();
MessagingCenter.Subscribe <TestPublisher>(subscriber, "test", p => MessagingCenterTestsCallbackSource.Increment(ref i));
GC.Collect();
GC.WaitForPendingFinalizers();
var pub = new TestPublisher();
pub.Test();
Assert.IsTrue(i == 5, "The static method should have incremented 'i'");
}
public void NothingShouldBeCollected()
{
var success = false;
_subscriber = new TestSubcriber(); // Using a class member so it doesn't get optimized away in Release build
var source = new MessagingCenterTestsCallbackSource();
MessagingCenter.Subscribe <TestPublisher>(_subscriber, "test", p => source.SuccessCallback(ref success));
GC.Collect();
GC.WaitForPendingFinalizers();
var pub = new TestPublisher();
pub.Test();
Assert.True(success); // TestCallbackSource.SuccessCallback() should be invoked to make success == true
}
public void NothingShouldBeCollected()
{
var success = false;
var subscriber = new TestSubcriber();
var source = new MessagingCenterTestsCallbackSource();
MessagingCenter.Subscribe <TestPublisher>(subscriber, "test", p => source.SuccessCallback(ref success));
GC.Collect();
GC.WaitForPendingFinalizers();
var pub = new TestPublisher();
pub.Test();
Assert.True(success); // TestCallbackSource.SuccessCallback() should be invoked to make success == true
}
public void SubscriberCollectableAfterUnsubscribeEvenIfHeldByClosure()
{
WeakReference wr = null;
new Action(() =>
{
var subscriber = new TestSubcriber();
wr = new WeakReference(subscriber);
MessagingCenter.Subscribe <TestPublisher>(subscriber, "test", p => subscriber.SetSuccess());
})();
Assert.IsNotNull(wr.Target as TestSubcriber);
MessagingCenter.Unsubscribe <TestPublisher>(wr.Target, "test");
GC.Collect();
GC.WaitForPendingFinalizers();
Assert.IsFalse(wr.IsAlive); // The Action target and subscriber were the same object, so both could be collected
}
public void ShouldBeCollectedIfCallbackTargetIsSubscriber()
{
WeakReference wr = null;
new Action(() =>
{
var subscriber = new TestSubcriber();
wr = new WeakReference(subscriber);
subscriber.SubscribeToTestMessages();
})();
GC.Collect();
GC.WaitForPendingFinalizers();
var pub = new TestPublisher();
pub.Test();
Assert.IsFalse(wr.IsAlive); // The Action target and subscriber were the same object, so both could be collected
}
