Question

I just started working on an existing grails project where there is a lot of code written and not much is covered by tests. The project is using Hudson with the Cobertura plugin which is nice. As I’m going through things, I’m noticing that even though there are not specific test classes written for code, it is being covered. Is there any easy way to see what tests are covering the code? It would save me a bit of time if I was able to know that information.
Thanks

Answer 1

What you want to do is collect test coverage data per test. Then when some block of code isn’t exercised by a test, you can trace it back to the test.

You need a test coverage tool which will do that; AFAIK, this is straightforward to organize. Just run one test and collect test coverage data.

However, most folks also want to know, what is the coverage of the application given all the tests? You could run the tests twice, once to get what-does-this-test-cover information, and then the whole batch to get what-does-the-batch-cover. Some tools ( ours included) will let you combine the coverage from the individual tests, to produce covverage for the set, so you don’t have to run them twice.

Our tools have one nice extra: if you collect test-specific coverage, when you modify the code, the tool can tell which individual tests need to be re-run. You need a bit of straightforward scripting for this, to compare the results of the instrumentation data for the changed sources to the results for each test.