Do not create test cases for scenarios with no steps.

To be consistent with the (Pickle) compiler in the Gherkin library,
test cases should not be created for scenarios with no steps.

Author: brasmusson

lib/cucumber/core/compiler.rb

@@ -45,7 +45,7 @@ def on_step(source)
         end
 
         def on_test_case(source)
-          Test::Case.new(test_steps, source).describe_to(receiver)
+          Test::Case.new(test_steps, source).describe_to(receiver) if test_steps.count > 0
           @test_steps = nil
           self
         end

spec/cucumber/core/compiler_spec.rb

@@ -157,6 +157,23 @@ def self.stubs(*names)
       end
     end
 
+    context 'empty scenarios' do
+      it 'does not create test cases for them' do
+        gherkin_documents = [
+          gherkin do
+            feature do
+              scenario do
+              end
+            end
+          end
+        ]
+        compile(gherkin_documents) do |visitor|
+          expect( visitor ).to receive(:test_case).never
+          expect( visitor ).to receive(:done).once.ordered
+        end
+      end
+    end
+
     describe Compiler::FeatureCompiler do
       let(:receiver) { double('receiver') }
       let(:compiler) { Compiler::FeatureCompiler.new(receiver) }

spec/cucumber/core/test/case_spec.rb

@@ -277,7 +277,7 @@ module Test
             gherkin = Gherkin::Document.new('features/treasure.feature', %{# language: en-pirate
               Ahoy matey!: Treasure map
                 Heave to: Find the treasure
-                  Gangway!: a map
+                  Gangway! a map
             })
             receiver = double.as_null_object
             expect( receiver ).to receive(:test_case) do |test_case|

spec/cucumber/core/test/filters/locations_filter_spec.rb

@@ -96,8 +96,6 @@ module Cucumber::Core
                 Given a table
                   | a | b |
                   | 1 | 2 |
-
-              Scenario: empty
           END
         end
 
@@ -112,13 +110,6 @@ def test_case_named(name)
           expect(receiver.test_case_locations).to eq [test_case_named('two').location]
         end
 
-        it 'matches the precise location of an empty scenario' do
-          location = test_case_named('empty').location
-          filter = Test::LocationsFilter.new([location])
-          compile [doc], receiver, [filter]
-          expect(receiver.test_case_locations).to eq [test_case_named('empty').location]
-        end
-
         it 'matches multiple locations' do
           good_location = Ast::Location.new(file, 8)
           bad_location = Ast::Location.new(file, 5)