make config file template source cookbook configurable

[mgreensmith]

Allows the wrapper cookbook author to provide the rabbitmq.config.erb in their wrapper cookbook. This is necessary if you want to eg. add configuration for plugins.

[jjasghar]

Interesting. I'm about to merge in some chefpsec tests, can you add one to cover this issue?

#168

[mgreensmith]

Hmm, I'm not certain how we would test this action any deeper than via your proposed test in #168 (https://github.com/jjasghar/rabbitmq/pull/168/files#diff-b38757f597e170ce2c611c84c7737807R49). Changing the attribute ['rabbitmq']['config_template_cookbook'] should not result in a different converge behavior. Your proposed test for the rabbitmq.config.erb template will still apply against this resource even if the template has been sourced from an external cookbook.

[jjasghar]

Yeah chewing on this, i think your right, we don't have a way we can write a good spec around this. I'm open to suggestions here; hopefully someone will also chime in :)

[tas50]

Just to chime in on the tests for this. Outside of using test kitchen with a mock wrapper cookbook there's not really a way to test this. The existing test process does ensure that adding this behavior doesn't break standard workflows though. I'm obviously biased since both @mgreensmith and I want this merged, but it's a fairly safe merge IMO.

[tas50]

+1