Add explicit mutator for or_asgn

lib/mutant.rb

@@ -70,6 +70,7 @@ require 'mutant/mutator/node/named_value/constant_assignment'
 require 'mutant/mutator/node/named_value/variable_assignment'
 require 'mutant/mutator/node/noop'
 require 'mutant/mutator/node/op_asgn'
+require 'mutant/mutator/node/or_asgn'
 require 'mutant/mutator/node/while'
 require 'mutant/mutator/node/super'
 require 'mutant/mutator/node/zsuper'

lib/mutant/mutator/node/generic.rb

@@ -16,7 +16,7 @@ module Mutant
           :regopt, :restarg, :resbody, :retry, :arg_expr,
           :kwrestarg, :kwoptarg, :kwarg, :undef, :module, :empty,
           :alias, :for, :xstr, :back_ref, :class,
-          :sclass, :match_with_lvasgn, :match_current_line, :or_asgn, :kwbegin
+          :sclass, :match_with_lvasgn, :match_current_line, :kwbegin
         )
 
       private

lib/mutant/mutator/node/or_asgn.rb

@@ -0,0 +1,30 @@
+# encoding: utf-8
+
+module Mutant
+  class Mutator
+    class Node
+
+      # OrAsgn mutator
+      class OrAsgn < Generic
+
+        handle(:or_asgn)
+
+        children :left, :right
+
+      private
+
+        # Emit mutations
+        #
+        # @return [undefined]
+        #
+        # @api private
+        #
+        def dispatch
+          super
+          emit_nil
+        end
+
+      end # OrAsgn
+    end # Node
+  end # Mutator
+end # Mutant

spec/unit/mutant/mutator/node/or_asgn/mutation_spec.rb

@@ -2,7 +2,7 @@
 
 require 'spec_helper'
 
-describe Mutant::Mutator::Node::Generic, 'or_asgn' do
+describe Mutant::Mutator::Node::OrAsgn, 'or_asgn' do
   let(:random_fixnum) { 5        }
   let(:random_string) { 'random' }
 
@@ -16,6 +16,7 @@ describe Mutant::Mutator::Node::Generic, 'or_asgn' do
     mutations << 'a ||= -1'
     mutations << 'a ||= 2'
     mutations << 'a ||= 5'
+    mutations << 'nil'
   end
 
   before do

spec/unit/mutant/mutator/node/send/mutation_spec.rb

@@ -41,6 +41,7 @@ describe Mutant::Mutator, 'send' do
       mutations = []
       mutations << 'foo ||= expression'
       mutations << 'nil.foo ||= expression'
+      mutations << 'nil'
     end
 
     it_should_behave_like 'a mutator'