output

$ rspec .
.F

Failures:

  1) foobar::package should install multiple versions of foobar
     Failure/Error: expect(chef_run).to install_package 'foobar_15'
       No package resource named 'foobar_15' with action :install found.
     # ./spec/package_spec.rb:14

Finished in 0.00221 seconds
2 examples, 1 failure

Failed examples:

rspec ./spec/package_spec.rb:12 # foobar::package should install multiple versions of foobar

package.rb

pkg_ver = node['foobar']['package_version']

if pkg_ver.kind_of? Array
  pkg_ver.each do |ver|
    package "foobar_#{ver}"
  end
elsif pkg_ver.kind_of? String
  package "foobar_#{pkg_ver}"
end

package_spec.rb

require 'chefspec'

describe "foobar::package" do

  chef_run = ChefSpec::ChefRunner.new.converge "foobar::package"

  it "should install version 15" do
    chef_run.node.foobar.package_version = '15'
    expect(chef_run).to install_package "foobar_15"
  end

  it "should install multiple versions of foobar" do
    chef_run.node.foobar.package_version = ['15', '16']
    expect(chef_run).to install_package 'foobar_15'
    expect(chef_run).to install_package 'foobar_16'
  end
end