private static async Task AssertUsesSynchronizationContext(int arity, bool?configureAwait, bool shouldUseSynchronizationContext)
{
var source = new TaskCompletionSource <object>();
var adapters = AwaiterAdapter.CreateAdapters(Enumerable.Repeat(source.Task, arity).ToArray(), continueOnCapturedContext: configureAwait);
var copyableContext = new CopyableSynchronizationContext();
using (TempSyncContext(copyableContext))
{
var resultSourcesByAdapterIndex = adapters.Select(_ => new TaskCompletionSource <SynchronizationContext>()).ToArray();
for (var i = 0; i < adapters.Count; i++)
{
var adapterIndex = i;
adapters[i].OnCompleted(() => resultSourcesByAdapterIndex[adapterIndex].SetResult(SynchronizationContext.Current));
}
source.SetResult(null);
var resultsByAdapterIndex = await Task.WhenAll(resultSourcesByAdapterIndex.Select(s => s.Task));
var expected = shouldUseSynchronizationContext ? copyableContext : null;
Assert.All(
adapters.Zip(resultsByAdapterIndex, (adapter, result) => (Adapter: adapter, Result: result)),
r => Assert.Same(expected, r.Result));
}
}
private static void AssertUsesSynchronizationContext(int arity, bool?configureAwait, bool shouldUseSynchronizationContext)
{
var source = new TaskCompletionSource <object>();
var adapters = AwaiterAdapter.CreateAdapters(Enumerable.Repeat(source.Task, arity).ToArray(), continueOnCapturedContext: configureAwait);
var copyableContext = new CopyableSynchronizationContext();
using (TempSyncContext(copyableContext))
{
var actualContinuationContextByAdapterIndex = new SynchronizationContext[adapters.Count];
for (var i = 0; i < adapters.Count; i++)
{
var adapterIndex = i;
adapters[i].OnCompleted(() => actualContinuationContextByAdapterIndex[adapterIndex] = SynchronizationContext.Current);
}
source.SetResult(null);
for (var i = 0; i < adapters.Count; i++)
{
if (shouldUseSynchronizationContext)
{
Assert.Same(expected: copyableContext, actual: actualContinuationContextByAdapterIndex[i]);
}
else
{
Assert.Null(actualContinuationContextByAdapterIndex[i]);
}
}
}
}