How to rspec test a Puppet class when a parameter needs a resource reference

Question

This may be a simple matter of mocking a resource, but...

class myclass (
  String stringParam,
  Integer intParam,
  File fileParam
) {
 # do some things
 $path = fileParam['title']
 $mode = fileParam['mode']
 # do some more things
 }

Now I want to write an rspec-puppet test for this class. How do I either create or mock a File resource and get it into the catalog that rspec-puppet uses, so that I can reference it?

The answers to this and this got me partway there, but everything I've tried has led to myClass complaining that it's being passed a string instead of a file reference.

...
let(:params) {{
  :stringParam => 'Here is my string',
  :intParam    => 238,
  :fileParam   => *??????,*
}}

Answer 1

There isn't really much support in rspec-puppet for this, as a class test parameters list is generated from the :params assuming only strings (or nested hashes/arrays etc. containing strings) or a couple of permitted symbol values used almost literally, :undef and :default. It doesn't have a way of passing in resource references.

A workaround exists that lets you put literal content into a manifest though, by passing an object that responds to the inspect method. For example, in your spec_helper.rb:

class ResourceReference
  def initialize(ref)
    @ref = ref
  end

  def inspect
    @ref
  end
end

And then in your spec:

let(:params) {{
  :stringParam => 'Here is my string',
  :intParam    => 238,
  :fileParam   => ResourceReference.new("File[/etc/foo]"),
}}

rspec-puppet will call the inspect method on the ResourceReference object which returns the string you've passed in. This should be placed in the manifest unchanged.

(This was originally used as a workaround for undef, which can now be passed as :undef.)

As an aside, you can set let(:pre_condition) { "..." } to add literal content to the test manifest before the generated class { ... }, but I don't think there's a way to use that here.

I'd strongly recommend filing a feature request against rspec-puppet.