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invoke function from its name as string
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Date: -- (:)
From: Ludovic Coquelle <lcoquelle@g...>
Subject: Re: [Caml-list] invoke function from its name as string
I like the "global test registry" of Andrej and will give it a try
(adapted to OUnit).
Thanks for all the advices!

On Fri, Mar 14, 2008 at 1:03 AM, Andrew Gacek <andrew.gacek@gmail.com> wrote:
> Andrej's solution is interesting since it lets you interleave the
>  regular code with the test code. For my own code, I keep all tests
>  isolated to separate files and in each file I maintain the tests as a
>  list of anonymous functions. As a made-up example I might have
>
>  let list_tests =
>   "List" >::: [
>     "Empty list has length zero" >::
>       (fun () ->
>          assert_equal 0 (List.length [])) ;
>
>     "Empty list appended to empty list is empty list" >::
>       (fun () ->
>          assert_equal [] ([] @ [])) ;
>
>     ...
>
>   ]
>
>  This structure makes it very easy to add new tests and does not
>  require me to come up with
>  convoluted_test_function_names_with_undersctores. The downside is that
>  tests end up being indented so much.
>
>  -Andrew
>
>  On Thu, Mar 13, 2008 at 11:41 AM, Andrej Bauer
>
> <Andrej.Bauer@fmf.uni-lj.si> wrote:
>
>
> > Ludovic Coquelle wrote:
>  >  > Thanks for this answer.
>  >  > Problem I'm trying to solve is the following:
>  >  >
>  >  > I use 'make_suite' which is a program that do regex matching on source
>  >  > code to extract a list of function that looks like OUnit tests; from
>  >  > this list, it write an ocaml source code file which is a test case
>  >  > that call all the previous functions found.
>  >  > (see: http://skydeck.com/blog/programming/unit-test-in-ocaml-with-ounit/)
>  >
>  >  I looked at the blog post. The idea is to interleave the source code
>  >  with special test functions and extract those automatically. You have
>  >  chosen to do this by searching the source code with regular expressions,
>  >  looking for functions with a certain name. If I may be honest and will
>  >  all due respect: this is a really horrible idea. It is fragile,
>  >  sensitive to mistakes, you have no guarantee that all the test functions
>  >  were actually found (say what if someone mispells the name of one of
>  >  them slightly), and so on. It is just really bad.
>  >
>  >  How about the following solution, in which I naively assume that test
>  >  functions are supposed to return bool, but this is easily fixed. Define
>  >  a module "Test" somewhat like this:
>  >
>  >  ---test.ml----
>  >  (** The list of tests registered by the source code. *)
>  >  let tests = ref []
>  >
>  >  (** Register a function as a test. *)
>  >  let register name test =
>  >    tests := (name, test) :: !tests
>  >
>  >  (** Run all tests, maybe we can combine this with OUnit? *)
>  >  let run_tests () =
>  >    List.iter
>  >      (fun (name,test) ->
>  >         if not (test ()) then failwith ("FAILED: " ^ name))
>  >      !tests
>  >  -------------
>  >
>  >  In your source code, whenever you want to have a test you just write:
>  >
>  >  Test.register "some_name" (fun () ->
>  >    (*test code here*)
>  >  *)
>  >
>  >  This is essentially the same overhead as what you have in your current
>  >  solution, except that it is robust, ocaml will check that it is ok, and
>  >  you do not have to come up with names of test functions of the form
>  >  test_... all the time. The names of tests are strings, they can be more
>  >  descriptive.
>  >
>  >  To run your program, you do not do anything special. There will be a
>  >  small initialization cost when the test functions are collected in the list.
>  >
>  >  Tu run the tests, you link your source code with something like
>  >
>  >  ---runtest.ml---
>  >
>  >  Test.run_tests ()
>  >
>  >  ---------------
>  >
>  >  You can easily extend this idea to using OUnit inside test.ml or do
>  >  whatever you like. The important thing is that you do not search the
>  >  source code in a naive and fragile way that requires to programmer to
>  >  follow arbitrary naming conventions.
>  >
>  >  Best regards,
>  >
>  >  Andrej
>  >
>  >
>  >
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