Allow a hook to be executed for all transactions (beforeEach hook)

[peterstrapp]

Currently hooks have to be applied to a specific transaction.

It would be useful to have "global" hooks that execute before each test, something like this:

before "ALL", (transaction) ->
  console.log 'Displayed before each test'

For now I am working around this limitation by calling runHooksForTransaction two more times (once for before and once for after) in add-hooks.js and passing in a fake transaction name of "ALL".

runner.before('executeTransaction', function(transaction, callback) {
    return runHooksForTransaction(hooks.beforeHooks['ALL'], transaction, callback);
});

[ecordell]

Can I ask what you need to do in a hook for every endpoint that can't be done with flags?

There's a fairly easy way to do this right now: run with --names, copy the list of names, make it an array, and then iterate over them.

Here's an example of mine:

{before, after} = require 'hooks'

endpoints = [
  "Authentication > Users Collection > Create a User",
  "Authentication > Sessions > Create a Session",
  # all endpoints ...
]

for endpoint in endpoints
  before endpoint, (transaction) ->
    delete transaction.expected.headers['Location']
    delete transaction.expected.headers['X-Total-Count']
    delete transaction.expected.headers['Link']

You can have multiple hooks for the same name, so it won't affect anything else.

[peterstrapp]

I'm templating parts of the blueprint file, substituting place-holders for values. I can't know upfront what endpoints exist as the blueprint file will be modified by other users. I don't want them to have to modify the hook file each time an endpoint is added.

If there's a way of getting the list of endpoints pragmatically, within the hook file, then your approach would be ideal.

[ecordell]

Transactions are exposed in hooks so you can do something like:

{before, after, transactions} = require 'hooks'

endpoints = transactions.map (currentValue, index, array) ->
  currentValue.name

for endpoint in endpoints
  before (transaction, done) ->
    #do something
    done()

[peterstrapp]

Thanks for the suggestion, I've just given it a try. Unfortunately it seems that 'transactions' isn't populated until after the hook file is executed.

[ecordell]

Unfortunately it seems that 'transactions' isn't populated until after the hook file is executed.

Hmm, that shouldn't be true - the whole point of exposing the transactions is so that they're available to use in hookfiles. Are you using the latest version of Dredd? Can you post an example of code that doesn't work?

[peterstrapp]

Yes, I'm using Dredd v0.3.1.

Executing the below hook file prints an empty object ("{}") therefore, when attempting to execute map on it (as in the code above) it fails.

dredd test.md http://a.domain.com -d -m POST --hookfiles=hook.coffee -l error

{before, after, transactions} = require 'hooks'
console.log transactions

[BrianHicks]

I'm seeing this too, also on Dredd v0.3.1.

[vadim-hbo]

Ditto Dredd 0.3.9

[dbryand]

I'm doing something very similar to this, but I set it all up in the beforeAll hook:

var hook  = require('hooks');

// This patches Dredd so that we can run a function beforeEach.
function setBeforeEach() {
  _.each(hook.transactions, function(transaction) {
    var hooked = hook.beforeHooks[transaction.name] || [];

    hooked.unshift(function(transaction, done) {
      console.log('seen before each');
      done();
    });

    hook.beforeHooks[transaction.name] = hooked;
  });
}

hook.beforeAll(function(done) {
  setBeforeEach();
});

[conord33]

Awesome patch @dbryand! I generalized it, in coffeescript, a little more to be used like the before hook.

# before each patch
hooks.beforeEach = (hook) -> 
  hooks.beforeAll (done) ->
    transactionKeys = Object.keys hooks.transactions
    for key in transactionKeys
      hooked = hooks.beforeHooks[key] || []
      hooked.unshift (transaction, done) ->
        hook(transaction)
        done()
      hooks.beforeHooks[key] = hooked
    done()

The method can be called like this

hooks.beforeEach (transaction) ->
  hookToRunBeforeEachTest()

[kuba-kubula]

Hi everyone,

In last month Dredd has undergone some refactoring (it also touched the hooks implementation) so the best approach right now is described in hooks documentation where the beforeAll workaround is taken from pieces of code here and there.

I'll keep this issue open until Dredd has direct support for the beroreEach method, ok?

cc. @conord33 @dbryand @peterstrapp @ecordell @BrianHicks