In the writing and running tests section of the dune docs. For ppx_inline_test the following stanza is suggested.
(library (name foo) (preprocess (pps ppx_inline_test)))
However, I’ve also encountered the following example in the stanza reference section of the docs
(tests (names mytest expect_test) <optional fields>)
I’m curious what the difference is? How would I know when to use libraries or tests?