gistfile1.txt

----------FUNCTION----------
Puppet::Parser::Functions.newfunction(:extract, :type => :rvalue, :doc => "Extract it!") do |args|
  raise Puppet::ParseError, "Please pass 2 arguments to the extract function, not #{args.length}" unless args.length == 2
  
  yaml_file  = args[0]
  yaml_field = args[1]

  raise Puppet::ParseError, "File #{yaml_file} not accessible to the extract function" unless File.exist?(yaml_file) and File.readable?(yaml_file)

  yaml_hash = YAML.load_file(yaml_file)
  yaml_hash[yaml_field] || 'VALUE NOT FOUND'
end


----------SPEC TEST---------
require 'puppet'
require 'rspec-puppet'

RSpec.configure { |config| config.mock_with :mocha }

describe Puppet::Parser::Functions.function(:extract) do
  let(:scope)    { PuppetlabsSpec::PuppetInternals.scope }
  let(:filename) { '/tmp/myfile.yaml' }
  let(:field)    { 'name' }
  let(:yamldata) { { 'name' => 'gary', 'color' => 'blue' } }

  it 'should return a value from a yaml file' do
    File.stubs(:exist?).with(filename).returns(true)
    File.stubs(:readable?).with(filename).returns(true)
    YAML.stubs(:load_file).with(filename).returns(yamldata)
    scope.function_extract([filename, field]).should == 'gary'
  end
end


----------RSPEC RUN------------

Failures:

  1) function_extract should return a value from a yaml file
     Failure/Error: scope.function_extract([filename, field]).should == 'gary'
     Mocha::ExpectationError:
       unexpected invocation: File.exist?('/opt/puppet/lib/ruby/gems/1.9.1/gems/trollop-1.16.2/lib/puppet/parser/functions/extract.rb')
       satisfied expectations:
       - allowed any number of times, not yet invoked: File.readable?('/tmp/myfile.yaml')
       - allowed any number of times, not yet invoked: File.exist?('/tmp/myfile.yaml')
       - allowed any number of times, not yet invoked: Psych.load_file('/tmp/myfile.yaml')
     # ./custom_functions/spec/unit/puppet/parser/functions/extract_spec.rb:17:in `block (2 levels) in <top (required)>'