Re: [Caml-list] testing private functions with oUnit

[Malcolm Matalka <mmatalka@gmail.com>]

I believe .Net has the concept of visibility at the module, package, and
external layer.  Something like this would be nice, although I have no
idea what it would look like, in Ocaml since often I want to create
modules internal to a package to make the code cleaner but those
functions have to be visible to everyone.

But, IMO, even though it would be nice I don't think it's stopping
myself from writing anything.

Gerd Stolpmann <info@gerd-stolpmann.de> writes:

> I think there is some missing functionality in OCaml: a mechanism to
> grant access to something that is normally hidden. This is not only
> important for unit testing but for debugging in general (remember that
> even ocamldebug cannot break module abstractions).
>
> What about this idea: modules (and only modules) can have associated
> visibility attributes. These are set with the definition or in the
> signature, e.g.
>
> module Implementation { "debug" } = struct ... end
>
> and are part of the cmi file. This imposes a restriction on the module
> path - Implementation may then only occur as part of a module path if it
> is explicitly allowed (e.g. that could be a command-line switch, and the
> debugger would allow everything).
>
> When using this technique, you'd normally put everything into an
> Implementation sub-module that is access-protected, and you'd redefine
> what is part of the regular interface:
>
> module Implementation { "debug" } = struct ... end
>
> import Implementation
>   (* or redefine definition by definition: 
>      let my_function = Implementation.my_function *)
>
> And in the mli (which may now even be superfluous unless you want to
> document the API):
>
> val my_function : ...
> module Implementation { "debug" } : sig ... end
>
> If there was a special ANY module type that unifies with anything:
>
> module Implementation { "debug" } : ANY
>
> This would then simply export all definitions.
>
> There could be additional utilities for stripping definitions with
> access control tokens from the cmi files. The whole point is to grant
> the developer of a certain library more rights than the user of a
> library.
>
> Gerd
>
>
> Am Sonntag, den 28.09.2014, 19:06 -0400 schrieb Eric Cooper:
>> I'd like to write unit tests for functions not exported in a .mli
>> file.  The only way I can see is to remove the .mli file while
>> building the test, so the whole .ml file is visible.  Is there a better
>> way, preferably integrated with ocamlmake + findlib?
>> 
>> -- 
>> Eric Cooper             e c c @ c m u . e d u
>>