Fix rubocop validations (#251)

Gemfile

@@ -2,6 +2,12 @@ source "https://rubygems.org"
 
 gemspec
 
+gem 'rake', '~> 13.0', '>= 13.0.6'
+gem 'rspec', '~> 3.11', '>= 3.11.0'
+gem 'rubocop', '~> 1.29', '>= 1.29.1'
+gem 'rubocop-packaging', '~> 0.5', '>= 0.5.1'
+gem 'unindent', '~> 1.0', '>= 1.0'
+
 # To hack on Cucumber together with any of these libraries, uncomment the line below:
 # gem 'cucumber-gherkin', path: '../common/gherkin/ruby'
 # gem 'cucumber-messages', path: '../common/messages/ruby'

cucumber-core.gemspec

@@ -25,12 +25,6 @@ Gem::Specification.new do |s|
   s.add_dependency 'cucumber-messages', '>= 19', '< 22'
   s.add_dependency 'cucumber-tag-expressions', '~> 5.0', '>= 5.0.4'
 
-  s.add_development_dependency 'rake', '~> 13.0', '>= 13.0.6'
-  s.add_development_dependency 'rspec', '~> 3.11', '>= 3.11.0'
-  s.add_development_dependency 'rubocop', '~> 1.29', '>= 1.29.1'
-  s.add_development_dependency 'rubocop-packaging', '~> 0.5', '>= 0.5.1'
-  s.add_development_dependency 'unindent', '~> 1.0', '>= 1.0'
-
   s.files            = Dir[
     'CHANGELOG.md',
     'CONTRIBUTING.md',

lib/cucumber/core/event.rb

@@ -47,7 +47,7 @@ def event_id
         private
 
         def underscore(string)
-          string.to_s.gsub(/::/, '/').
+          string.to_s.gsub('::', '/').
           gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2').
           gsub(/([a-z\d])([A-Z])/, '\1_\2').
           tr("-", "_").

spec/cucumber/core/test/doc_string_spec.rb

@@ -84,7 +84,7 @@ module Test
           end
 
           it 'delegates #gsub to the content string' do
-            expect( doc_string.gsub(/n/, '_') ).to eq 'co_te_t'
+            expect( doc_string.gsub('n', '_') ).to eq 'co_te_t'
           end
 
           it 'delegates #split to the content string' do