Fix failing tests with Ruby < 2.5

Also remove writer test which is not super useful for now

Author: vincent-psarga

lib/cucumber/core/gherkin/writer.rb

@@ -85,7 +85,10 @@ class Background
 
           private
           def statements
-            prepare_statements comments_statement, tag_statement, name_statement, description_statement
+            prepare_statements comments_statement,
+              tag_statement,
+              name_statement,
+              description_statement
           end
         end
 
@@ -97,13 +100,14 @@ class Rule
 
           default_keyword 'Rule'
 
-          elements :scenario
+          elements :example, :scenario
 
           private
           def statements
             prepare_statements comments_statement,
               name_statement,
-              description_statement
+              description_statement,
+              NEW_LINE
           end
         end
 
@@ -126,6 +130,12 @@ def statements
           end
         end
 
+        class Example < Scenario
+          include Indentation.level 4
+
+          default_keyword 'Example'
+        end
+
         class ScenarioOutline
           include HasElements
           include HasOptionsInitializer

spec/cucumber/core/gherkin/parser_spec.rb

@@ -92,10 +92,23 @@ def self.source(&block)
         context "when scenario is inside a rule" do
           source do
             feature do
-              rule do
-                scenario do
-                  step 'text'
-                end
+              rule description: "My castle, my rules" do
+                scenario name: "My scenario"
+              end
+            end
+          end
+
+          it "passes on the pickle" do
+            expect( receiver ).to receive(:pickle)
+            parse
+          end
+        end
+
+        context "when example is inside a rule" do
+          source do
+            feature do
+              rule description: "My castle, my rules" do
+                example name: "My example"
               end
             end
           end
@@ -106,16 +119,16 @@ def self.source(&block)
           end
         end
 
-        context "when there are multiple rules and scenarios" do
+        context "when there are multiple rules and scenarios or examples" do
           source do
             feature do
-              rule do
-                scenario do
+              rule description: "First rule" do
+                scenario name: "Do not talk about the fight club" do
                   step 'text'
                 end
               end
-              rule do
-                scenario do
+              rule description: "Second rule"do
+                example name: "Do not talk about the fight club" do
                   step 'text'
                 end
               end

spec/cucumber/core/gherkin/writer_spec.rb

@@ -233,27 +233,6 @@ module Cucumber::Core::Gherkin
           end
         end
       end
-
-      context 'with rules' do
-        xit 'can have a description' do
-          source = gherkin do
-            feature do
-              rule name: "Simple", description: "My castle, my rule" do
-                scenario name: "My scenario"
-              end
-            end
-          end
-
-          expect( source.body ).to eq <<-END.unindent
-          Feature:
-
-            Rule: Simple
-              My castle, my rules
-
-              Scenario: My scenario
-          END
-        end
-      end
     end
 
     it 'generates a complex feature' do