#### osnap

OCaml random snapshot testing

Random snapshot testing library for OCaml.

The Documentation can be found here. This library
uses QCheck generators to generate random values
for snapshots.

### Build

Build from source:

``````\$ git clone git@github.com:vch9/osnap.git
\$ dune build
``````

You can also install with opam:

``````\$ opam install osnap
``````

The code is now released under the MIT license.

### An introduction to the library

The library intends to test differences on results between two versions.

#### Binary Exponentiation

Let's say we write a function computing the exponentiation.

``````let rec exponentiation x n =
if n = 0 then 1
else if n = 1 then x
else exponentiation x (n - 1) * x

let test =
let open Osnap in
let spec = Spec.(small_int ^> small_int ^>> string_of_int) in
let path = ".osnap/exponentiation" in

let test = Test.make ~spec ~path ~count:5 ~name:"exponentiation" exponentiation

let _ =
Osnap.Runner.(run_tests ~mode:Interactive [ test ])
``````

In the above, we first provide a naive implementation of the exponentiation.
Then, we create a test with the according specification using `Osnap` combinator.

``````exponentiation 14	4	38416
exponentiation 13	11	1792160394037
exponentiation 11	1	11
exponentiation 12	2	144
exponentiation 2	14	16384
``````

As we agree with our function result, we promote the change by typing `Y`.
We try to improve our function efficiency with binary exponentiation.

``````let rec binary_expo x n =
if n = 0 then 1
else if n mod 2 = 0 then
let tmp = binary_expo x (n / 2) in
tmp * tmp
else x * binary_expo x (n - 1)

let test =
let open Osnap in
let spec = Spec.(small_int ^> small_int ^>> string_of_int) in
let path = ".osnap/exponentiation" in

Test.make ~spec ~path ~count:5 ~name:"exponentiation" binary_expo

let _ = Osnap.Runner.(run_tests ~mode:Interactive [ test ])
``````

Finally, we get the following result:

``````Recap:
1 passed
0 promoted
0 ignored
0 fails
``````

`Osnap` has not found any difference between the old and new snapshot :heavy_check_mark:.

Install
Published
05 Sep 2021
Sources
0.1.1.tar.gz
`md5=8bc581190594d8248cb151c4e733ed57`
`sha512=5eaf6d441e0bc24fd8935e98b8ef21fea5da2fa30a48186bb5b61e8013dd0b860a21b019ff5ed42745247e1b9229a71bbd7b4ee97d30ba68f593f328cad3306b`
Dependencies
odoc
`with-doc`
alcotest
`with-test & >= "1.4.0"`
ppx_deriving
`>= "5.2.1"`
patdiff
`>= "v0.14.0"`
qcheck
`>= "0.17"`
ocaml
`>= "4.12.0"`
dune
`>= "2.8.0"`
Reverse Dependencies