My project is using a websocket server. Only for testing purposes, I also have an erlang websocket client implementation which resides in the test/ folder along with the tests. Now, when I run the tests via rebar with {cover_enabled, true} in my rebar.config, I also get coverage reported for the modules of the websocket client. I don't want this in my reports. Cover documentation says I should create a cover specification file containing {excl_mods, [websocket_client]}. But how do I convince rebar to use this file? Cover documentation: http://www.erlang.org/doc/apps/common_test/cover_chapter.html http://www.erlang.org/doc/man/cover.html rebar: https://github.com/basho/rebar