Unit testing or integration testing?

Question

Here it says that this example is more of an explanation of framework than best practice because of the conflation of integration/unit testing concepts: http://docs.flexunit.org/index.php?title=Using_Asynchronous_Startup
My question is, how do you define a line here between unit testing and integration testing? What kind of UI components asynchronous tests are then considered to be unit tests and not yet integration tests? Many books recommend having 100% code coverage with unit tests. How would this example look like, to be considered only a unit test and not integration test?

Answer 1

The question about which levels of testing to do are really dependent upon you. Let me explain a bit more.
If you are building an application, and only an application, then functional testing probably covers most of your needs. In an application environment, you have a relatively narrow pathway of options and interactions that a user might follow. So long as you test those options well, your app will probably work as well.
Where I see the real value of unit testing is testing for the unknowns. If you have a class that will be used in multiple applications in multiple ways, or perhaps it is intended to be a reusable class where others in your organization will use it in the future, then you want lower level testing. You want to have the best coverage you can because you want to know that, regardless of the way someone chooses to use the code, it will likely function or at least fail gracefully.
The same is true for integration. If I am creating a Flex component, then I can unit test part of it, but not all. So, I want to use integration tests to ensure that it works in as many circumstance as possible. Further, Flex components have a life cycle, so testing them when they are not on the display list isn't really a valid test..
So, to summarize, I see unit and integration w/Flex about testing possibilities and trying to achieve realistic code coverage for known and possible use cases. I see functional testing as testing those components in very specific use cases.
Which do you need? Depends. Are you developing reusable components across (n) projects, likely the first 2 and maybe the last. Are you an application developer testing that an application works in documented business cases? Just functional will likely work.
Hope that helps,
Mike