OUnit user guide : OUnitDiff

# Module OUnitDiff

    module OUnitDiff: sig .. end

Unit tests for collection of elements

This module allows to define a more precise way to display differences between collection of elements. When collection differ, the tester is interested by what are the missing/extra elements. This module provides a `diff` operation to spot the difference quickly between two sets of elements.

Example:

    open OUnit;;

    module EInt =
    struct
      type t = int
      let compare = ( - )
      let pp_printer = Format.pp_print_int
      let pp_print_sep = OUnitDiff.pp_comma_separator
    end

    module ListInt = OUnitDiff.ListSimpleMake(EInt);;

    let test_diff () =
      ListInt.assert_equal
        [1; 2; 3; 4; 5]
        [1; 2; 5; 4]
    ;;

    let _ =
      run_test_tt_main ("test_diff" >:: test_diff)
    ;;

when run this test outputs:

    OUnit: expected: 1, 2, 3, 4, 5 but got: 1, 2, 5, 4
    differences: element number 2 differ (3 <> 5)

- Author(s): Sylvain Le Gall
- Since 1.1.0

### Signatures

    module type DIFF_ELEMENT = sig .. end

Definition of an element

    module type S = sig .. end

Definition of standard operations

### Implementations

    module SetMake: functor (D : DIFF_ELEMENT) -> S
      with type e = D.t

Collection of elements based on a Set, elements order doesn't matter

    module ListSimpleMake: functor (D : DIFF_ELEMENT) -> S
      with type e = D.t and type t = D.t list

Collection of elements based on a List, order matters but difference display is very simple.

    val pp_comma_separator : Stdlib.Format.formatter -> unit -> unit