Add multi-version support to provider unit tests

Add support for testing against multiple kernel and iptables versions,
to ensure that features gated by kernel or iptables version aren't
rendered un-testable.  Also, pull the handy construct for handling the
addition of '--wait' in later iptables versions in the ip6tables test
cases over to iptables tests as well, because with multi-version
support, the test cases for iptables will start to need it as well.

Author: greatflyingsteve

spec/unit/puppet/provider/ip6tables_spec.rb

@@ -124,6 +124,14 @@ def stub_iptables
   describe 'when working out general_args' do
     HASH_TO_ARGS6.each do |test_name, data|
       describe "for test data '#{test_name}'" do
+        before :each do
+          # Allow examples to stub kernel and iptables versions
+          allow(Facter.fact(:ip6tables_version)).to receive(:value).and_return(data[:ip6tables_version]) if data[:ip6tables_version]
+          allow(Facter.fact(:kernelversion)).to receive(:value).and_return(data[:kernel_version]) if data[:kernel_version]
+          # Unload existing provider so provider features get re-assessed after we stub the determining facts
+          Puppet::Type.type(:firewall).unprovide(:ip6tables)
+        end
+
         let(:resource) { Puppet::Type.type(:firewall).new(data[:params]) }
         let(:provider6) { Puppet::Type.type(:firewall).provider(:ip6tables) }
         let(:instance) { provider6.new(resource) }

spec/unit/puppet/provider/iptables_spec.rb

@@ -243,11 +243,20 @@
   describe 'when working out general_args' do
     HASH_TO_ARGS.each do |test_name, data|
       describe "for test data '#{test_name}'" do
+        before :each do
+          # Allow examples to stub kernel and iptables versions
+          allow(Facter.fact(:iptables_version)).to receive(:value).and_return(data[:iptables_version]) if data[:iptables_version]
+          allow(Facter.fact(:kernelversion)).to receive(:value).and_return(data[:kernel_version]) if data[:kernel_version]
+          # Unload existing provider so provider features get re-assessed after we stub the determining facts
+          Puppet::Type.type(:firewall).unprovide(:iptables)
+        end
+
         let(:resource) { Puppet::Type.type(:firewall).new(data[:params]) }
         let(:provider) { Puppet::Type.type(:firewall).provider(:iptables) }
         let(:instance) { provider.new(resource) }
 
         it 'general_args should be valid' do
+          data[:args].unshift('--wait') if instance.general_args.flatten.include? '--wait'
           expect(instance.general_args.flatten).to eq(data[:args])
         end
       end