ContinueAfter Unit Tests

continue-after-unit-tests.cs

public class TheContinueAfterMethod
{
    [Fact]
    public void RunsNextItemAfterCompletion()
    {
        var stringSequence = new[] { "one", "two", "three" }.ToObservable();
        var observed = new List<String>();

        Observable.Return(123).ContinueAfter(() => stringSequence)
            .Subscribe(observed.Add);

        observed[0].ShouldEqual("one");
        observed[1].ShouldEqual("two");
        observed[2].ShouldEqual("three");
    }

    [Fact]
    public void RunsNextItemOnlyOnceAfterCompletion()
    {
        var stringSequence = new[] { "uno", "dos", "tres" }.ToObservable();
        var initialSequence = new[] { 1, 2, 3, 4 }.ToObservable();
        int callCount = 0;
        var observed = new List<String>();

        initialSequence.ContinueAfter(() =>
        {
            callCount++;
            return stringSequence;
        })
            .Subscribe(observed.Add);

        callCount.ShouldEqual(1);
        observed[0].ShouldEqual("uno");
        observed[1].ShouldEqual("dos");
        observed[2].ShouldEqual("tres");
    }

    [Fact]
    public void RunsNextItemAfterObservableCompletesWithEmptySequence()
    {
        var stringSequence = new[] { "하나", "둘", "셋" }.ToObservable();
        var observed = new List<String>();

        Observable.Empty<int>()
            .ContinueAfter(() => stringSequence)
            .Subscribe(observed.Add);

        observed[0].ShouldEqual("하나");
        observed[1].ShouldEqual("둘");
        observed[2].ShouldEqual("셋");
    }

    [Fact]
    public void ForwardsExceptionsFromOriginalObservable()
    {
        var stringSequence = new[] { "하나", "둘", "셋" }.ToObservable();
        var observed = new List<String>();
        Exception caught = null;

        Observable.Throw<int>(new Exception("Will we catch this?"))
            .ContinueAfter(() => stringSequence)
            .Subscribe(observed.Add, e => caught = e);

        observed.Count.ShouldEqual(0);
        caught.Message.ShouldEqual("Will we catch this?");
    }
}