Illustration of stubbing other things, like guard expressions, in ChefSpec

default.rb

service 'true_guard' do
  action :start
  only_if { File.exist?('/tmp/trueguard') }
end

service 'false_guard' do
  action :start
  not_if { File.exist?('/tmp/falseguard') }
end

default_spec.rb

require 'chefspec'

describe 'chefspecguards::default' do
  let(:chef_run) { ChefSpec::Runner.new.converge(described_recipe) }

  it 'includes resource that have guards that evaluate to true' do
    File.stub(:exist?).and_return(true) # could also stub with args
    expect(chef_run).to start_service('true_guard')
  end

  it 'excludes resources that have guards evaluated to false' do
    File.stub(:exist?).and_return(true)
    expect(chef_run).to_not start_service('false_guard')
  end

end