var observable = Observable.Range(1, 5); observable.AssertValue(3);
var observable = Observable.Interval(TimeSpan.FromSeconds(1)).Take(5); observable.AssertValueIn this example, the `AssertValue` method is used to verify that the `observable` sequence emits a value that is an even number (based on the provided predicate condition) and has a value of 2 within the first 5 seconds of the sequence running. The `AssertValue` method is part of the `System.Reactive.Linq` namespace in the Rx library.(2, x => x % 2 == 0);