public async Task GetOrAdd_ExtentionMethod_protected_from_running_twice_in_multi_threaded_code()
{
var cache = new MultiThreadProtectedDecorator(new SimpleInmemoryCache());
int ctorCallCount = 0;
Func <string, int> ctor = _ => {
Interlocked.Increment(ref ctorCallCount);
return(ctorCallCount);
};
Task <int> t1 = Task.Run(() => cache.GetOrAdd("Key", ctor));
Task <int> t2 = Task.Run(() => cache.GetOrAdd("Key", ctor));
await Task.WhenAll(t1, t2);
Assert.That(ctorCallCount, Is.EqualTo(1));
}
public async Task GetOrAdd_protected_from_running_twice_in_multi_threaded_code()
{
var cache = new MultiThreadProtectedDecorator(new SimpleInmemoryCache());
int ctorCallCount = 0;
Func <string, int> slowCtor = _ => {
// slow down the first ctor call to ensure second thread always see the cache
// as empty even though this ctor has been called to add the item
Thread.Sleep(TimeSpan.FromMilliseconds(100));
Interlocked.Increment(ref ctorCallCount);
return(ctorCallCount);
};
Func <string, int> ctor = _ => {
Interlocked.Increment(ref ctorCallCount);
return(ctorCallCount);
};
Task <int> t1 = Task.Run(() => cache.GetOrAdd("Key", slowCtor));
Task <int> t2 = Task.Run(() => cache.GetOrAdd("Key", ctor));
await Task.WhenAll(t1, t2);
Assert.That(ctorCallCount, Is.EqualTo(1));
}