$ make tests COVER=1
Erlang.mk provides support for code coverage via the tool cover that comes with Erlang/OTP. Code coverage lets you see what parts of your code are covered by the tests.
To run tests with code coverage enabled, simply define COVER=1 either on the command line or in your Makefile:
$ make tests COVER=1
When running the targets tests or check the code coverage report will be built automatically. This is not the case for test framework specific targets, however. In those cases you can generate the reports manually:
$ make eunit proper COVER=1 $ make cover-report
Note that Common Test has some support for cover built-in and that it will generate code coverage reports in the Common Test logs regardless. The report that Erlang.mk generates is however common to all test frameworks and might be more useful.
By default Erlang.mk will include all the applications in the code coverage report, except external dependencies.
To include some dependencies in the report, you can define the COVER_DEPS variable:
COVER_DEPS = cowlib
When using multi application repositories you can exclude some applications by defining the COVER_APPS variable:
COVER_APPS = presence backend
By default Erlang.mk will store coverdata files and code coverage reports under the cover/ directory. The variables COVER_DATA_DIR and COVER_REPORT_DIR can be set to use a different location.
The target all.coverdata will take all existing coverdata files and merge them into one:
$ make all.coverdata