public ThreadSafeDictionaryCache([CanBeNull] IEqualityComparer <TKey> equalityComparer)
{
_cache
= new ThreadSafeLazyRef <ImmutableDictionary <TKey, TValue> >(
() => ImmutableDictionary <TKey, TValue>
.Empty
.WithComparers(equalityComparer));
}
public void Has_value_is_false_until_value_accessed()
{
var safeLazy = new ThreadSafeLazyRef <string>(() => "s");
Assert.False(safeLazy.HasValue);
Assert.Equal("s", safeLazy.Value);
Assert.True(safeLazy.HasValue);
}
public async Task Can_exchange_value()
{
var safeLazy = new ThreadSafeLazyRef <string>(() => "");
var tasks = new List <Task>();
for (var i = 0; i < 10; i++)
{
tasks.Add(Task.Run(() => safeLazy.ExchangeValue(s => s + "s")));
}
await Task.WhenAll(tasks);
Assert.Equal("ssssssssss", safeLazy.Value);
}
public async Task Can_initialize_from_multiple_threads_and_initialization_happens_only_once()
{
var counter = 0;
var safeLazy = new ThreadSafeLazyRef <string>(() => counter++.ToString());
var tasks = new List <Task>();
for (var i = 0; i < 10; i++)
{
tasks.Add(Task.Run(() => safeLazy.Value));
}
await Task.WhenAll(tasks);
Assert.Equal(1, counter);
}