document testable

[martindemello]

I found out about adding new testable types from this blogpost; there is nothing in the project docs about it.

[craigfe]

Hi @martindemello,

By "the project docs", do you mean the README in this repository? The generated docs at http://mirage.github.io/alcotest/alcotest/Alcotest/ do reference the Alcotest.testable helper function for building testable values, as well as the implementation of the Alcotest.testable type (which is concrete, so can be constructed directly).

[martindemello]

yeah, i meant the README and the examples. i didn't see the generated docs because they are also not linked to from the README :) but the package was easy enough to get up to speed with once i got the basic idea; i'll try to contribute some more docs once i've used it for a bit.

[craigfe]

yeah, i meant the README and the examples. i didn't see the generated docs because they are also not linked to from the README :)

Good point! They are linked from a little docs badge, but it's not very visible – hopefully #320 will improve that.

i'll try to contribute some more docs once i've used it for a bit.

Thanks!

[mjambon]

The approach using a first-class module of type TESTABLE requires a lot of mental gymnastics to simply provide a pair ~~to_string/of_string~~ to_string/equal. Please include an example in the API docs.

[mjambon]

Here's an example for a fictitious module Fizz providing a to_string function and an equal function with the obvious types:

let fizz = Alcotest.testable (Fmt.of_to_string Fizz.to_string) Fizz.equal
...
let test_something () =
  Alcotest.check fizz "equal" Fizz.zero (Fizz.of_string "0")