cjdns/doc/coverage.md

Test Coverage

Test coverage is for determining how many (what percentage) of lines of code in the project have been executed by a given test. This is a BAD METRIC, you can have 100% test coverage on a project that still doesn't work ! Keep in mind before you go off joining the church of industrial software design, there are a lot of people who take these things extremely seriously and they are annoying.

Test coverage can provide you with 2 pieces of information, 1. where the tests are not reaching and 2. where there might be dead code which is never executed (and should therefore be deleted).

Checking coverage with gcov

1. Build with GCOV=1 aka GCOV=1 ./do (make sure you are using gcc to compile)
2. For the file you are interested in, find the corresponding .i file in the build directory, for net/InterfaceController.c the file will be ./build_linux/net_InterfaceController_c.i

3. run gcov on the .i file but without the .i extension for example: $ gcov-5 ./build_darwin/net_InterfaceController_c You should see a result which looks like the following:

   File 'net/InterfaceController.c' Lines executed:55.58% of 412 Creating 'InterfaceController.c.gcov'

4. review the resulting .gcov file atom ./InterfaceController.c.gcov lines which were not touched by any test will have ##### before them.

Checking coverage for a particular test

Same as the global coverage check except you will want to disable tests at the beginning so you do not check for all tests GCOV=1 NO_TEST=1 ./do then run the test you want ./build_linux/test_testcjdroute_c CryptoAuth_fuzz_test then run gcov on the file you want to check.

Last but not least

Clean up the enormous pile of crap which gcov generates !