Add custom function validation

[erikgustafson-klarna]

This PR allows using user defined functions for validating and reading values from JSON fields.

[andreineculau]

I'm sorry but I'm going to reject this PR.
A major advantage of KATT is that the scenarios (aka blueprints) are language-abstract.

That said, you can do what you want without any change in KATT by introducing a new validation type e.g.

{
  "type": "klarna_erlang",
  "erl_eval": "some_module:some_validation_fun(arg1, arg2)"
}

KlarnaJson =
  fun(recall_body) ->
    [ fun katt_callbacks_json:recall_body/4
    ];
  fun(parse) ->
    [ fun katt_callbacks_json:parse/5
    ];
  fun(validate_body) ->
    [ fun katt_callbacks_json:validate_body/3
    ],
  fun(validate_type) ->
    [ fun katt_callbacks_json:validate_type/7
    , fun klarna_callbacks_json:validate_type/7
    ],
katt:run("klarna_erlang_scenario.apib", [], [{ext, KlarnaJson}]).

where

klarna_callbacks_json:validate_type/7 is basically like https://github.com/for-GET/katt/blob/master/src/katt_callbacks_json.erl#L98 but not for the "klarna_erlang" type, with your code from https://github.com/for-GET/katt/pull/29/files#diff-0ca8b609d9263432236ebef8184c89c0R489

[andreineculau]

Out of curiousity, what type of validation are you doing in your custom funs? i.e. what validation is not supported by KATT today?

[erikgustafson-klarna]

Okay,

Regards Erik

On Wed, Feb 24, 2016 at 1:12 PM, Andrei Neculau notifications@github.com
wrote:

I'm sorry but I'm going to reject this PR.
A major advantage of KATT is that the scenarios (aka blueprints) are
language-abstract.

That said, you can do what you want without any change in KATT by
introducing a new validation type e.g.

{
"type": "klarna_erlang",
"erl_eval": "some_module:some_validation_fun(arg1, arg2)"
}

KlarnaJson =
fun(recall_body) ->
[ fun katt_callbacks_json:recall_body/4
];
fun(parse) ->
[ fun katt_callbacks_json:parse/5
];
fun(validate_body) ->
[ fun katt_callbacks_json:validate_body/3
],
fun(validate_type) ->
[ fun katt_callbacks_json:validate_type/7
, fun klarna_callbacks_json:validate_type/7
],katt:run("klarna_erlang_scenario.apib", [], [{ext, KlarnaJson}]).

where

klarna_callbacks_json:validate_type/7 is basically like
https://github.com/for-GET/katt/blob/master/src/katt_callbacks_json.erl#L98
but not for the "klarna_erlang" type, with your code from
https://github.com/for-GET/katt/pull/29/files#diff-0ca8b609d9263432236ebef8184c89c0R489

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#29 (comment).

[erikgustafson-klarna]

There are 3 things we need to do

1. Making sure that a list contains at least some elements regardless of
   order.
2. Making sure that a JSON structure like this one

[
{type:"elv"},
{type:"invoice"},
.....
]

contains at least elements with type elv and invoice. Order in this case is
unknown and extra elements could be present

1. Using regex to pick out values from a string to store for use further
   down in the test

// Erik

On Wed, Feb 24, 2016 at 1:14 PM, Andrei Neculau notifications@github.com
wrote:

Out of curiousity, what type of validation are you doing in your custom
funs? i.e. what validation is not supported by KATT today?

—
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#29 (comment).

[andreineculau]

1. Already supported, that's why we introduced the "set" validation type e.g. https://github.com/for-GET/katt/blob/master/test/katt_run_validate_type_set_tests.erl#L162
2. don't see how this is different than 1. All structures accept unknown elements, unless {{unexpected}} is given.
3. also already supported https://github.com/for-GET/katt/blob/master/test/katt_run_tests.erl#L449

[erikgustafson-klarna]

Cool, we are still running on a pretty old version of katt internally in
Klarna and the set feature was not included in that

Thanks for your time

On Wed, Feb 24, 2016 at 1:45 PM, Andrei Neculau notifications@github.com
wrote:

Already supported, that's why we introduced the "set" validation type
e.g.
https://github.com/for-GET/katt/blob/master/test/katt_run_validate_type_set_tests.erl#L162
2.

don't see how this is different than 1. All structures accept unknown
elements, unless {{unexpected}} is given.
3.

also already supported
https://github.com/for-GET/katt/blob/master/test/katt_run_tests.erl#L449

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#29 (comment).

[sstrigler]

This use case rings a bell, a thing I wanted to take care of a while ago. :(

[sstrigler]

Ah m)