public static async Task <T> PollForCondition <T>(
this ITestScheduler scheduler,
Func <T> getState,
Func <T, bool> condition,
CancellationToken cancellationToken)
{
var tcs = new TaskCompletionSource <T>();
void CheckCondition()
{
try
{
var state = getState();
if (condition(state))
{
tcs.SetResult(state);
}
}
catch (Exception e)
{
tcs.SetException(e);
}
}
using (scheduler.RegisterPollCallback(CheckCondition))
using (cancellationToken.Register(tcs.SetCanceled))
{
if (!cancellationToken.IsCancellationRequested)
{
CheckCondition(); // Complete immediately if already met
}
return(await tcs.Task);
}
}
private static async Task <Exception> Timeout(
this ITestScheduler scheduler,
TimeSpan timeout,
CancellationToken cancellationToken)
{
var deadline = scheduler.TimeNow + timeout;
var completionSource = new TaskCompletionSource <object>();
void CheckTimeout()
{
if (scheduler.TimeNow >= deadline)
{
completionSource.SetException(new TimeoutException());
}
}
using (scheduler.RegisterPollCallback(CheckTimeout))
using (cancellationToken.Register(completionSource.SetCanceled))
{
return(await completionSource.Task.ExpectException());
}
}
