Add return statement mutations

Gemfile

@@ -6,27 +6,4 @@ gem 'to_source',           :git => 'https://github.com/mbj/to_source.git'
 gem 'melbourne',           :git => 'https://github.com/mbj/melbourne.git'
 gem 'inflector',           :git => 'https://github.com/mbj/inflector.git'
 
-group :development do
-  gem 'rake',    '~> 0.9.2'
-  gem 'yard',    '~> 0.8.1'
-  gem 'rspec',   '~> 2'
-end
-
-group :guard do
-  gem 'guard',         '~> 1.3.2'
-  gem 'guard-bundler', '~> 1.0.0'
-  gem 'guard-rspec',   '~> 1.2.1'
-  # Remove this once https://github.com/nex3/rb-inotify/pull/20 is solved.
-  # This patch makes rb-inotify a nice player with listen so it does not poll.
-  gem 'rb-inotify', :git => 'https://github.com/mbj/rb-inotify'
-end
-
-group :metrics do
-  gem 'flay',            '~> 1.4.2'
-  gem 'flog',            '~> 2.5.1'
-  gem 'reek',            '~> 1.2.8', :git => 'https://github.com/dkubb/reek.git'
-  gem 'roodi',           '~> 2.1.0'
-  gem 'yardstick',       '~> 0.5.0'
-  gem 'yard-spellcheck', '~> 0.1.5'
-  gem 'pelusa',          '~> 0.2.1'
-end
+eval(File.read(File.join(File.dirname(__FILE__),'Gemfile.devtools')))

Gemfile.devtools

@@ -0,0 +1,22 @@
+group :development do 
+  gem 'rake',    '~> 0.9.2'
+  gem 'rspec',   '~> 2.12.0'
+  gem 'yard',    '~> 0.8.3'
+end
+
+group :guard do
+  gem 'guard',         '~> 1.5.4'
+  gem 'guard-bundler', '~> 1.0.0'
+  gem 'guard-rspec',   '~> 2.1.1'
+  gem 'rb-inotify', :git => 'https://github.com/mbj/rb-inotify'
+end
+
+group :benchmarks do
+  gem 'rbench', '~> 0.2.3'
+end
+
+platform :jruby do
+  group :jruby do
+    gem 'jruby-openssl', '~> 0.7.4'
+  end
+end

Guardfile

@@ -4,7 +4,7 @@ guard :bundler do
   watch('Gemfile')
 end
 
-guard :rspec, :version => 2 do
+guard :rspec, :all_on_start => false do
   # run all specs if the spec_helper or supporting files files are modified
   watch('spec/spec_helper.rb')                      { 'spec/unit' }
   watch(%r{\Aspec/(?:lib|support|shared)/.+\.rb\z}) { 'spec/unit' }

lib/mutant.rb

@@ -69,6 +69,7 @@ require 'mutant/mutator/block'
 require 'mutant/mutator/noop'
 require 'mutant/mutator/call'
 require 'mutant/mutator/define'
+require 'mutant/mutator/return'
 require 'mutant/mutator/if_statement'
 require 'mutant/mutator/receiver_case'
 require 'mutant/loader' 

lib/mutant/mutator/noop.rb

@@ -6,7 +6,6 @@ module Mutant
       # Literal references to self do not need to be mutated. 
       handle(Rubinius::AST::Self)
       # Some unimplemented mutations
-      handle(Rubinius::AST::Return)
       handle(Rubinius::AST::ElementAssignment)
       handle(Rubinius::AST::AttributeAssignment)
       handle(Rubinius::AST::Not)

lib/mutant/mutator/return.rb

@@ -0,0 +1,29 @@
+module Mutant
+  class Mutator
+    # Mutator for return statements
+    class Return < self
+
+      handle(Rubinius::AST::Return)
+
+    private
+
+
+      # Emit mutants
+      #
+      # @return [undefined]
+      #
+      # @api private
+      #
+      def dispatch
+        value = node.value
+        if value
+          emit(value)
+        else
+          emit_nil
+        end
+      end
+
+    end
+  end
+end
+

spec/unit/mutant/mutator/literal/nil_spec.rb

@@ -0,0 +1,13 @@
+require 'spec_helper'
+
+describe Mutant::Mutator::Literal, 'nil' do
+  let(:source) { 'nil' }
+
+  let(:mutations) do
+    mutations = []
+
+    mutations << 'Object.new'
+  end
+
+  it_should_behave_like 'a mutator'
+end

spec/unit/mutant/mutator/return/mutation_spec.rb

@@ -0,0 +1,21 @@
+require 'spec_helper'
+
+describe Mutant::Mutator, 'return' do
+
+  context 'return without value' do
+    let(:source) { 'return' }
+
+    let(:mutations) { ['nil'] }
+
+    it_should_behave_like 'a mutator'
+  end
+
+  context 'return with value' do
+    let(:source) { 'return foo' }
+
+    let(:mutations) { ['foo'] }
+
+    it_should_behave_like 'a mutator'
+  end
+
+end