Ensure FacterImpl consistency between example groups

Using the 'rspec' facter implementation we could sometimes get in a case
where the values of FacterImpl and Puppet.runtime[:facter] diverged
between example groups.

Because rspec-puppet overrides facts using the FacterImpl constant
(which is only set once), Puppet.runtime[:facter] would point to a
different instance of FacterTestImpl with no available facts, causing
calls to Puppet.runtime[:facter].value to fail.

To prevent this from happening, set Puppet.runtime[:facter] to the value
of FacterImpl; this way we make sure Puppet.runtime[:facter] and
FacterImpl operate on the same instance of FacterTestImpl.

Author: GabrielNagy

lib/rspec-puppet/adapters.rb

@@ -237,8 +237,8 @@ def setup_puppet(example_group)
         case RSpec.configuration.facter_implementation.to_sym
         when :rspec
           if supports_facter_runtime?
-            Puppet.runtime[:facter] = proc { RSpec::Puppet::FacterTestImpl.new }
-            set_facter_impl(Puppet.runtime[:facter])
+            set_facter_impl(RSpec::Puppet::FacterTestImpl.new)
+            Puppet.runtime[:facter] = FacterImpl
           else
             warn "Facter runtime implementations are not supported in Puppet #{Puppet.version}, continuing with facter_implementation 'facter'"
             RSpec.configuration.facter_implementation = 'facter'

spec/unit/adapters_spec.rb

@@ -224,6 +224,18 @@ def context_double(options = {})
         expect(FacterImpl).to be_kind_of(RSpec::Puppet::FacterTestImpl)
       end
 
+      it 'ensures consistency of FacterImpl in subsequent example groups' do
+        context = context_double
+
+        # Pretend that FacterImpl is already initialized from a previous example group
+        Puppet.runtime[:facter] = RSpec::Puppet::FacterTestImpl.new
+        Object.send(:const_set, :FacterImpl, Puppet.runtime[:facter])
+
+        allow(RSpec.configuration).to receive(:facter_implementation).and_return('rspec')
+        subject.setup_puppet(context)
+        expect(FacterImpl).to eq(Puppet.runtime[:facter])
+      end
+
       it 'raises if given an unsupported option' do
         context = context_double
         allow(RSpec.configuration).to receive(:facter_implementation).and_return('salam')