I came to Erlang/OTP from python world, where I'm using unittest library. Typical test environment will be presented by some TestSuite for entire application and TestCases with test methods for different modules from subpackages of application.
My first application on Erlang is cowboy-based web application. It has some modules which are required by cowboy framework and its behavior plus some set of my custom modules, let's say: parsers.erl, encoders.erl, fetchers.erl.
In the beginning of development I was writing tests inside that modules (in methods method_name_test) and then running them with eunit. But as for me it was kind of inconvenient. In a week or so I got in touch with commont_test framework. And as for newcomer from python world - CT with its suites, grouping, setup-ing, configs, execution order model looked like very familiar.
Considering my application - what is the proper way of writing test suites? Should I prepare separate suites for different modules (as for me it will create some overhead) or introduce single test suite for application and in different groups put test cases for separate modules? Would be great to read about tests organizing in real-world Erlang applications.
The stdlib in Erlang/OTP has a single Common Test suite per module in the library.