Question

I am working on some code coverage for my applications. Now, I know that code coverage is an activity linked to the type of tests that you create and the language for which you wish to do the code coverage.

My question is: Is there any possible way to do some generic code coverage? Like in, can we have a set of features/test cases, which can be run (along with a lot more specific tests for the application under test) to get the code coverage for say 10% or more of the code?

More like, if I wish to build a framework for code coverage, what is the best possible way to go about making a generic one? Is it possible to have some functionality automated or generalized?

Answer 1

I’m not sure that generic coverage tools are the holy grail, for a couple of reasons:

1. Coverage is not a goal, it’s an instrument. It tells you which parts of the code are not entirely hit by a test. It does not say anything about how good the tests are.
2. Generated tests can not guess the semantics of your code. Frameworks that generate tests for you only can deduct meaning from reading your code, which in essence could be wrong, because the whole point of unittesting is to see if the code actually behaves like you intended it too.
3. Because the automated framework will generate artificial coverage, you can never tell wether a piece of code is tested with a proper unittest, or superficially tested by a framework. I’d rather have untested code show up as uncovered, so I fix that.

What you could do (and I’ve done 😉 ) is write a generic test for testing Java beans. By reflection, you can test a Java bean against the Sun spec of a Java bean. Assert that equals and hashcode are both implemented (or neither of them), see that the getter actually returns the value you pushed in with the setter, check wether all properties have getters and setters.

You can do the same basic trick for anything that implements ‘comparable’ for instance.

It’s easy to do, easy to maintain and forces you to have clean beans. As for the rest of the unittests, I try to focus on getting important parts tested first and thouroughly.

Coverage can give a false sense of security. Common sense can not be automated.