Re: [Caml-list] invoke function from its name as string

["Andrew Gacek" <andrew.gacek@gmail.com>]

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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