public static async Task Main(string[] args) { if (args.Contains("--async")) { var syncContext = new XunitAsyncTestSyncContext(null); // new Nito.AsyncEx.AsyncContext().SynchronizationContext using (syncContext.AsTemporarySynchronizationContext()) { TestExtensions.DefaultMainTestProjectImplementation(args); } var exception = await syncContext.WaitForCompletionAsync(); var _ = exception switch { AggregateException a when a.InnerExceptions.Count == 1 => throw a.InnerExceptions[0], Exception e => throw e, null => (object)null, }; } else { TestExtensions.DefaultMainTestProjectImplementation(args); } }