So I have some challenging code I would like to refactor. The challenge is that it depends on Database queries, EJB and Java serverFaces. Not simultaneously but close to it.
A good example would be a geocoder. Getting meaningful results depending on multiple queries to the DB depending on the data entered and stored. The code might also reference other helper classes and look them up via the JSF framework.
What are the best strategies for testing this sort of code? Should I try to separate out my code as much as possible? Should I use mocking instead? What has worked for other people?
Well, the short answer is “yes”.
You’re going to need, first of all, to factor the code sufficiently to construct unit tests at all. What you’re describing is excessively complicated to apply the usual unit test methods, and what you would get in any case is more like a higher-level acceptance test.
Now, as far as that factoring goes, you have several possible approaches, and you will probably use them all.
Test the data base queries themselves, using an external script.
Construct an appropriate mock for the components directly accessing the DB, in order to see what happens against known results.
Build unit tests using a JUnit like framework for units of functionality.
Examine the state of the art to see if you can usefully test the output HTML against unit tests.