Delayed Constraint

DelayedConstraint delays evaluation of another constraint, optionally polling until the constraint passes or the timeout expires. This is useful for testing asynchronous operations or eventual consistency.

Usage

<constraint>.After(int delayInMilliseconds)
<constraint>.After(int delayInMilliseconds, int pollingInterval)
<constraint>.After(int delay).Seconds
<constraint>.After(int delay).Minutes.PollEvery(int interval).MilliSeconds

Examples

[Test]
public void DelayedConstraint_Examples()
{
    var flag = 0; // Use int for Interlocked
    Task.Run(async () =>
    {
        await Task.Delay(50);
        Interlocked.Exchange(ref flag, 1);
    });

    // Poll until condition is true (or timeout)
    Assert.That(() => Interlocked.CompareExchange(ref flag, 0, 0) == 1,
        Is.True.After(500).MilliSeconds.PollEvery(50).MilliSeconds);
}

Fluent Time Syntax

[Test]
public void DelayedConstraint_Fluent_Examples()
{
    var counter = 0;
    Task.Run(async () =>
    {
        await Task.Delay(50);
        Interlocked.Exchange(ref counter, 10);
    });

    // Fluent time syntax
    Assert.That(() => Interlocked.CompareExchange(ref counter, 0, 0),
        Is.GreaterThan(0).After(1).Seconds.PollEvery(100).MilliSeconds);
}

Time Modifiers

.Seconds
.Minutes
.MilliSeconds    // Note capital 'S'

Default unit is milliseconds when no modifier is specified.

Notes

Use delegates (() => value) not direct values, since values are captured at call time.
When polling, the delegate may be called multiple times - avoid side effects.
The .After() modifier applies to the entire constraint expression preceding it.
Without polling, the constraint waits the full delay before checking once.