Extend and check test coverage

- (Instructor) Now, what we also need to do…is make sure that we successfully parse the dates…and if we couldn't parse the dates we need to…return a explicit failure there.…I'm going to be slightly lazy about that…and simply say try with…And we probably really want to be a bit more explicit…about what's gone wrong there so I'm just…going to put a quick to do…And let's add some test cases for that…I probably should have done the test cases first…But there we go.…So let's say those are dates…let's see if we successfully return a failure for those…and we do and you can kind of see…that we might want to add some more test cases here…just to make sure we've exercised all the paths.…

By the way though you can see here…this tells you which paths you've exercised.…If there's a green blob and a line of code…it means that at least you've been through that line…of code in your tests.…Let's just prove that by commenting at those tests.…And you can see there's no coverage for that branch.…