Test unhappy paths

- [Instructor] So what's expected of some invalid text.…Well, expected is an Outcome.Failure,…and let's for the moment…just hard wire the error message in the test.…We're going to clearly need to call parse to do this test.…So let's say Parse text,…and let's have a little look at the types here.…So expected is an outcome of some type…that the compiler doesn't know about yet.…An actual is a query.…So we're not going to have very good results…when we're comparing.…

We're trying to do an AreEqual on an outcome and a query,…so we really need to make sure…that our Parse thing actually returns an outcome.…So let's move that text to there…and let us make sure that the return type,…let's say let result equals…and then just assign that records,…and now we're going to return a Outcome.Success of result.…

We haven't done the exception unhappy path yet,…but at least that makes the type overs of parse…be an outcome of type query.…Trouble is of course…that this will have broken our first test,…and indeed you can see red all over the place here…