(FACT-2535) Allow interpolation of Facter.fact('fact_name')

lib/models/resolved_fact.rb

@@ -22,5 +22,9 @@ def legacy?
     def core?
       type == :core
     end
+
+    def to_s
+      @value.to_s
+    end
   end
 end

spec/facter/facter_spec.rb

@@ -166,6 +166,20 @@
       expect(result).to be_instance_of(Facter::ResolvedFact).and(having_attributes(value: 'Ubuntu'))
     end
 
+    it 'can be interpolated' do
+      user_query = 'os.name'
+
+      allow(fact_manager_spy).to receive(:resolve_facts).and_return([os_fact])
+      allow(fact_collection_spy)
+        .to receive(:build_fact_collection!)
+        .with([os_fact])
+        .and_return(fact_collection_spy)
+      allow(fact_collection_spy).to receive(:value).with('os', 'name').and_return('Ubuntu')
+      # rubocop:disable Style/UnneededInterpolation
+      expect("#{Facter.fact(user_query)}").to eq('Ubuntu')
+      # rubocop:enable Style/UnneededInterpolation
+    end
+
     it 'return no value' do
       user_query = 'os.name'
 

spec/facter/model/resolved_fact_spec.rb

@@ -23,6 +23,17 @@
     it 'responds to core? method with false' do
       expect(resolved_fact.core?).to be(true)
     end
+
+    # rubocop:disable Style/UnneededInterpolation
+    it 'can be interpolated' do
+      expect("#{resolved_fact}").to eq('fact_value')
+    end
+
+    it 'interpolation of nil value will be empty string' do
+      resolved = Facter::ResolvedFact.new('fact_name', nil)
+      expect("#{resolved}").to eq('')
+    end
+    # rubocop:enable Style/UnneededInterpolation
   end
 
   context 'when is an invalid type' do