IObservable extensions for testing

ObservableExtensions.cs

    public static class ObservableExtensions
    {
        public static Func<bool> WasObserved<T>(this IObservable<T> o, T expected)
        {
            var wasExpectedObserved = false;
            var result = o.Subscribe(s =>
            {
                wasExpectedObserved = s.Equals(expected);
            });

            return () =>
            {
                result.Dispose();
                return wasExpectedObserved;
            };
        }

        public static Func<IEnumerable<T>> CaptureObserved<T>(this IObservable<T> o)
        {
            var result = new List<T>();
            var sub = o.Subscribe(s =>
            {
                result.Add(s);
            });

            return () =>
            {
                sub.Dispose();
                return result;
            };
        }
    }